annual report 2012 - ciematasociación euratom – ciemat .- annual report 2012 2 1.4.2 plasma...

Asociación EURATOM CIEMAT para Fusión

Annual Report 2012

INDEX INTRODUCTION 11

1 PROVISION OF SUPPORT TO THE ADVANCEMENT OF THE ITER PHYSICS

BASIS 13

1.1 Development of candidate operating scenarios 13

1.1.1 ELM physics and control 13

1.1.1.1 ELM studies in JET with visible Fast Camera. 13

1.1.1.2 The effect of ELM pacing via vertical kicks on the access to stationary H-

mode with good confinement (H98~1) on JET 13

1.1.2 contribution to JET results in view of ITER operation 14

1.3 Energy and particle confinement and transport 14

1.3.1 L-H physics 14

1.3.1.1 Characterization of the dynamical coupling between flows and

fluctuations in different magnetic configurations (q scan) during the L-H transition in TJ-II.

14

1.3.2 Momentum transport 15

1.3.2.2. Damping mechanisms of flows: 15

1.3.2.3 Driving mechanisms of zonal flows: 15

1.3.2.4 Electromagnetic turbulence and Maxwell stresses 16

1.3.3 Impurity transport studies 16

1.3.3.1 See 3.1.3.1 17

1.3.4 Isotope effect 17

1.3.4.1 Report on the impact of the isotopic effect on plasma confinement (H / D)

and amplitude of long-range correlations (zonal flows) 17

1.4 MHD stability and plasma control 17

1.4.1 ELM physics 17

1.4.1.1 Electromagnetic turbulent structures 17

1.4.1.2 Determination of plasma stability using resonant field amplification in JET

17

Asociación Euratom – CIEMAT .- Annual Report 2012 2

1.4.2 Plasma control 18

1.5 Power and particle exhaust. Plasma-wall interaction 18

1.5.1 Deposition in gaps and thermo-oxidation by NO2 18

1.5.2 Activities oriented to the validation of Li as a PFC for a Fusion reactor 19

1.5.3 Reduction of the sputtering yield of W by in-situ nitriding 19

1.5.4 Edge transport and particle and impurity source 19

1.5.4.1 Radial plasma transport and recycling of neutrals. 19

1.6 Physics of plasma heating and current drive 19

1.6.1 Dependence of plasma fluctuations on RF stray radiation 19

1.7 Energetic particle physics 20

1.7.1 Fast ion studies. 20

1.7.2 Alfvén eigenmode properties 20

1.7.3 Effect of ECH application on Alfvén Eigenmodes activity 20

1.8 Theory and modelling for ITER and DEMO 21

1.8.1 Plasma Heating (NBI) 21

1.8.2 Computational Developments 21

2 DEVELOPMENT OF PLASMA AUXILIARY SYSTEMS 22

2.1 Heating and current drive systems 22

2.1.1 Electron Bernstein Waves Heating experiments in TJ-II 22

2.1.2 NBI heating studies: Ion trajectory calculation 22

2.1.3 ECH activities in TJ-II 22

2.1.3.1 Changes in the gyrotron radiation properties, induced by a small amount

of reflected modulated power. 22

2.1.3.2 Second harmonic X mode breakdown experiments. 23

2.2 Plasma Diagnostics 23

2.2.1 Development of plasma diagnostics in TJ-II 23

2.2.1.1. Calibration of the multi-foil soft x-ray diagnostic (M4F) for core electron

temperature estimations. 23

2.2.1.2 Ion temperature measurements based on atomic beam measurements

and RFA diagnostic developed by IST. 23


2.2.1.3 Commissioning of second HIBP injector / analyzer for zonal flow studies

in TJ-II. (Capital expenditure excluded unless included in EFDA Task Agreements) 24

2.2.1.4 Development of a pellet injector for TJ-II 24

2.2.1.5. The Diagnostic Neutral Beam Injector and associated instrumentation 24

2.2.1.7. Studies on double pulse Thomson scattering measurements 26

2.2.1.8. NPA upgrading 26

2.2.1.9 Two-dimensional imaging of edge plasma electron density and

temperature. 27

2.2.1.10 Investigation of non-thermal electrons in the boundary region of the TJII

stellarator from I-V Langmuir probe characteristics 27

2.2.1.11. Linear array for electron temperature measurements (M4FA) 27

2.2.2 Diagnostic exploitation and development in JET 28

2.2.2.1 Commissioning and measurements of intensified fast visible cameras for

plasma-wall studies in JET 28

2.2.3 Development of plasma diagnostics in W7X: IR interferometry 28

2.2.3.1 Development of a modular system of CO2 interferometer diagnostic 28

2.2.4 Diagnostic development in ITER 29

2.2.4.1 Reflectometry 29

2.2.4.2 Visible – IR wide angle viewing system:Consortium CEA / CIEMAT /

ENEA / HAS / IST 29

2.2.4.3 Thomson Scattering 29

2.2.5 Reflectometry simulations 30

2.2.5.1 Reflectometry simulations: Development of a 3D full-wave code relevant

for ITER. 30

2.2.6 Advanced data analysis techniques 30

2.2.6.1 Disruption prediction 31

2.2.6.2 Confinement transitions 31

2.2.6.3 Image processing 32

2.2.6.4 Other works 33

2.3 Real Time Measurement and Control 33

2.3.1. Advanced data acquisition systems 33

2.3.2 Real-time disruption predictors 33


3 DEVELOPMENT OF CONCEPT IMPROVEMENTS AND ADVANCES IN

FUNDAMENTAL UNDERSTANDING OF FUSION PLASMAS 35

3.1.2 Impurity transport 35

3.1.2.1. Impurity confinement. 35

3.1.2 Experimental investigation of profiles structures and plasma instabilities 35

3.1.2.1 Dynamical coupling between gradients and transport. 35

3.2 Understanding of plasma characteristics for improved concepts 36

3.2.1 Design of an optimised stellarator using Genetic Algorithms and grid

computing 36

3.2.2 Retention and Recycling of H/D in solid and liquid Lithium 36

3.2.3 Island dynamics studies 36

3.3 Other experimental studies 37

3.3.1 Non-thermal ion studies 37

3.3.1.1. Fast ion slowing down time measurements 37

3.3.1.2. Suprathermal ions in TJ-II plasmas. 37

3.3.2 Dust studies 37

3.3.2.1 Dust studies in TJ-II. 37

3.3.3 MHD studies 37

3.3.3.1. MHD activity and radial transport barriers in TJ-II plasmas 37

3.3.3.2 Plasma current dependence of coherent modes frequency in low-density

NBI heated plasmas. 38

3.4 Theory and modelling 38

3.4.1 Neoclassical studies 38

3.4.2 Gyrokinetic equation developments 38

3.4.3 EUTERPE code development 39

3.4.4 MHD studies 40

3.4.4.1 MHD properties of H-mode transition 40

3.4.5 Transport and turbulence basic research 40

3.4.5.1 Mathematical results on non-Gaussian processes 40

3.4.5.2 Uncorrelated Lorentzian pulses and edge turbulence 41

3.5 TJ-II Engineering and Operation 41


3.5.1 Engineering activities 41

3.5.1.1 Activities in the TJ-II experiment 41

3.5.1.1.1 Technical operation of TJ-II 41

3.5.1.1.2 Maintenance and upgrading of systems and components 42

3.5.1.1.3 Installation of new equipment 44

3.5.2 Operation of TJ-II 45

3.5.2.1 Operation of the ECH system 47

3.5.2.1.1 General maintenance and improvements tasks 47

3.5.2.1.2 Experimental characterization 47

3.5.2.2 Operation of the NBI heating system 47

3.5.2.2.1 NBI operation 47

3.5.2.2.2 Ion Source conditioning 49

3.5.2.2.3 NBI Maintenance 49

3.5.2.2.4 NBI Upgrades 51

4 EMERGING TECHNOLOGIES 55

4.1 Development of material science and advanced materials for DEMO 55

4.1.1 Functional materials 55

4.1.1.1 Production of advanced Li silicates 55

4.1.1.2 Ion radiation evaluation of Li ceramics 55

4.1.1.3 Corrosion and compatibility of Li silicates 57

4.1.2 Ceramic insulators 58

4.1.2.1 Radiation evaluation of silica glasses 58

4.1.2.2 Ionoluminescence characterization of light ions on insulator materials 58

4.1.2.3 Characterization of H and He on insulating surfaces 59

4.1.2.4 Radiation effects on magnetic sensors and cables 59

4.1.2.5 Radiation effects on other IR/VIS diagnostics components 60

4.1.2.6 Definition of materials requirements in DEMO: ceramic insulators 60

4.1.3 Nanostructured ODS ferritic steels development (ODSFS Task Agreement) 60

4.1.3.1 Microstructural characterization of ODS/FeCr alloys 60

4.1.3.2 Radiation effects on ODS steels 62


4.1.3.3 Production and characterization of ODS steels 63

4.1.4 Tungsten and Tungsten Alloys Development (WWALLOY Task Agreement)

65

4.1.4.1 Brazing development 65

4.1.4.2 W-V and W-Ti ODS alloys development 66

4.1.4.3 ODS W-TiC and W-Ti alloys development 67

4.1.4.4 Oxidation resistant W-alloys development 69

4.1.5 Nanostructured ODS and no-ODS Cu based materials development (High

Heat Flux Materials Task, HHFMAM Agreement) 70

4.1.6 SiC materials 71

4.1.6.1 Production of SiC/SiC low termal conductivity composites for DCLL

applications 71

4.1.6.2 Characterization of SiC materials for DEMO 72

4.2 Materials modelling 72

4.2.1 Radiation Effects Modelling and Experimental Validation (REMEV Task

Agreement) 72

4.2.1.1 Rate Theory modelling of He evolution and its interaction with

microstructure in Fe 72

4.2.1.2 Synergetic effects of H and He in Fe 73

4.2.1.3 Experiments for modelling validation: He desorption in Fe and other

model materials 74

4.2.1.4 Experiments for modelling validation: Resistivity measurements 75

4.2.2 Modelling of insulator and functional materials 75

4.2.2.1 H in diamond 75

4.2.3 Plasma Wall materials modelling 75

4.2.3.1 Rate Theory modelling of defect evolution in irradiated W 75

4.2.3.2 Modelling of neutron irradiation effects on W 76

4.2.4 Radiation effects code improvement and development 77

4.2.4.1 Methodology for PKA evaluation 77

4.2.4.2 Tools for MCNP and CAD interfacing 77

4.2.4.3 Development of coupled radiation transport and activation calculations 78

4.3 Techniques for controlling tritium inventory 78


4.3.1 Tritium modelling 78

4.3.1.1 Tools development for tritium plant modelling 78

4.3.1.2 LIBRETTO irradiation modelling 79

4.3.1.3 Developing of a facility for the validation of a permeator against vacuum

79

4.3.1.4 Design and manufacture of a vacuum-permeator prototype 80

4.4 Development of HT superconductors for DEMO 80

4.4.1 Assessment for RE-123 fusion cable joints 80

4.5 Fusion Safety issues 81

4.5.1 Neutronics 81

4.5.1.1 Radiation and dose mapping evaluation of DEMO of Blanket activation 81

4.5.1.2 Neutronic study to shield the upper vertical port of DEMO 81

4.5.1.3 Evaluation of radiation load at TF coils 82

4.5.1.4 Evaluation of Blanket activation 82

4.5.1.5 Neutronic and activation assessments of a DCLL DEMO model 83

4.5.2 Balance of Plant related issues 84

4.5.2.1 Development of a LiPb-Supercritical CO2 heat exchanger 84

4.5.2.2 Energy Storage requirements for a pulsed fusion power plant 84

4.5.2.3 Electrical power output requirements of a fusion power plant 85

4.5.2.4 Electrical power output Nuclear Fusion Safety and Environment:

Modeling HT and HTO transport in the Atmosphere 86

4.6 Remote handling and RAMI 87

4.6.1 RAMI design guidelines for fusion facilities 87

4.6.1.1 RAMI activities for DEMO 87

4.6.2 Remote Handling (RH) 88

4.6.2.1 Innovative methods for pipe flange joining/separation by brazing and

associated testing technologies 88

4.6.2.2 Evaluation of dose rate during shutdown periods 89

4.6.2.3 Design of interface between UPP and tools for UPP RH operation for

ITER 89

5 TRAINING, PUBLIC INFORMATION AND SERF 91


5.1 Training 91

5.1.1 ERASMUS MUNDUS Educational activities (Master and PhD programmes).

91

5.1.2 Goal oriented training: 91

5.1.3 EFDA Fellowships: 92

5.1.4 Technofusion Summer Course. 92

5.1.5 Other training activities 92

5.2. Public Information 92

5.3. Technology transfer 92

5.4. Socioeconomics Studies for Fusion 92

5.4.1 EFDA Times Model 92

5.4.2 Public perception of Fusion research 93

5.4.2.1 Public Discourse about Nuclear Energy before and after Fukushima

accident (WP12-SER-ACIF-1) 93

6 OTHER ACTIVITIES CONTRIBUTING TO THE EURATOM FUSION PROGRAMME

94

6.1 Activities related to the Broader Approach 94

6.1 1 IFMIF/EVEDA Project 94

6.1.1.1 Introduction 94

6.1.1.2 Accelerator Facilities: RF system 94

6.1.1.3 Accelerator Facilities: Beam Dump & HEBT 95

6.1.1.4 Accelerator Facilities: Diagnostics 97

6.1.1.5 Accelerator Facilities: DTL & MS 98

6.1.1.6 Accelerator Facilities: Safety and Radioprotection 99

6.1.1.7 Test and Target activities: RH Engineering 101

6.1.1.8 Test and Target activities: Medium Flux modules engineering 102

6.1.1.9 Test and Target activities: Low Flux module 103

6.4.1.10 Test and Target activities: Start-up Monitoring Module 103

6.1.1.11. Design Integration: Safety 103

6.1.1.12. Design Integration: RAM evaluation 104


6.1.1.13. Neutronics study for the installation of the LBVM in the medium flux

area of IFMIF 106

6.1.2. JT-60 SA Cryostat 106

6.1.2.1. Activities in the Broader Approach. The Cryostat for JT-60SA 106

6.1.3. DEMO R&D 107

6.1.3.1. SiC/SiC characterization 107

6.1.3.2. Insulators ceramics 108

6.2. Dual Coolant Breeder Blankets Programme 108

6.2.1. Overview of Tecno_Fus project 108

6.2.2. Tecno_Fus DCLL Breeder Blanket design 109

6.2.3. Tecno_Fus Neutronics studies 109

6.2.4 Tecno_Fus Auxiliary systems development 109

6.2.5.Tecno_Fus MHD simulations and assessment 110

6.2.6. Tecno_Fus Tritium modelling 110

6.2.7. Tecno_Fus development of material production and characterization 110

6.3. Fusion Technology Facilities 111

6.2.1. Operation of presently available facilities 111

6.2.1.1. Operation of the van de Graaf accelerator 111

6.2.1.2. Operation of the “Nayade” irradiation facility 111

6.2.1.3. Irradiation line at the CMAM ion accelerator 112

6.2.1.4. Permeation and diffusivity facility at UPV 112

6.2.2. TechnoFusión 112

6.2.2.1. Introduction 112

6.2.2.2. Irradiation methods 114

6.2.2.3. Plasma-Wall Interaction 116

6.2.2.4. Characterization Techniques 116

6.2.2.5. Liquid Metal technologies 118

6.2.2.6. Remote Handling 118

6.2.2.7. Simulation Techniques 119

6.2.3. IFMIF (outside of the Broader Approach Agreement) 120


6.2.3.1. Use of IFMIF/EVEDA facilities for materials development 120

6.2.3.2. Comparison of different irradiation facilities 121

7 INERTIAL CONFINEMENT FUSION, KEEP IN TOUCH ACTIVITIES 122

7.1. Scientific development in target design 122

7.1.1 Radiation hydrodynamics and Atomic Physics 122

7.2. Physics and Technology IFE (and MFE) systems 123

7.2.1. State of the Art Inertial Fusion Energy by Laser 123

7.2.2. Materials advanced under Irradiation and Chamber Dynamics for IFE 124

7.2.3. IFE Systems: Reaction Chamber, Safety and Radio Protection 129


INTRODUCTION

This report describes the activity of the EURATOM-CIEMAT Association during

2012 and it is organized following mostly the scheme of the 2012 work program annexed to the

association contract.

The Association has continued its effort in generating a strong fusion technology

programme, which is reported in chapters 4 and 6 but this is accompanied with a solid

programme on plasma physics, oriented in two main lines:

a.- Plasma physics developments of general application and of interest for the

tokamak and ITER and results obtained in stellarators as test bench to understand tokamak

problems from an advantageous point if view. This is a very important contribution of the TJ-II

experiment, and example being the slower L-H transition, which allows for a very detailed study

of the mechanisms driving the transition. Chapter 1 shows a number of contributions which are

directly related to specific ITER problems: L-H transition physics, momentum transport, impurity

transport, fast particle physics, Tritium retention and extraction, role of nitrogen on W sputtering

reduction, carbon transport and deposition.

b.- Contributions to the development of the stellarator as a candidate for the steady

state reactor. The specific stellarator physics results are reported on Chapter 3: impurity

transport, role of fast particles, confinement transitions, confinement scaling and installation and

operation of a liquid lithium limiter. This chapter also includes the theory developments for

stellarators: design of reactor relevant stellarator configurations, island dynamics, neoclassical

transport, and advanced data analysis techniques applied to TJ-II. Details of the operation and

improvement of engineering TJ-II systems are also reported in chapter 3.

Chapter 3 covers also general theory developments, including gyrokinetic theory or

probabilistic transport, as well as theory for heating and diagnostic systems.

Another strong point of the TJ-II activity has been historically the development of

auxiliary systems, in particular diagnostics. Those activities are reported on chapter 2 and they

cover the development of new x ray diagnostics, the installation of the second Heavy Ion Beam

Probe, the new double pulse system for Thomson Scattering and the Diagnostic NBI.

International collaboration is mainly devoted to the joint experiment JET, W7X . JET

results are mainly reported in chapter 1: operation regimes, pedestal and ELM studies and

disruption prevention (this part reported on section 2.2). Other international collaborations are

related to the development of diagnostics, interferometry, for W7X (chapter 3) or the plasma

control techniques for TCV.

Emerging technologies is one of the areas of growing interest at the Association.

Chapter 4, section 4.1, includes a broad description of experimental activity, with lines of

development on: functional materials, insulators, structural metallic materials like tungsten and


ODS alloys, structural and functional SiC. Modelling activities, devoted to radiation effects

modelling and validation, insulators behaviour, effects on tungsten and activation phenomena

real also a growing area and they are extensively reported in section 4.2.

This chapter shows also the increasing level of activity in the area of Power Plant

Physic and Technology, with new lines of participation, including: high temperature

superconductors, remote handling, RAMI analysis, nuclear safety for Fusion, system code

design, neutronics studies, energy storage, efficient thermal cycles, tritium inventory control and

blanket technologies (the later mainly reported on chapter 6)

Chapter 5 describes training activities, focused on the Erasmus Mundus Master in

Fusion Physics and Technology, The European Doctoral College in Fusion and the participation

in Goal Oriented training systems: blankets (EUROBREED), remote handling (GOT-RH) and

two new projects, related to neutronics for diagnostics and materials modelling. Also in chapter

5 we include activities on public information, technology transfer and Socioeconomic studies,

which for 2012 were concentrated on the further development of the EFDA Times model and

the public perception of Fusion energy.

Chapter 6 describes, the IFMIF, JT60 and DEMO activities in the framework of the

Broader Approach (only for information) and also the emerging activity in dual coolant blanket

development as well as the experimental fusion technology facilities which form part of the

“Technofusion “ project.

Finally Chapter 7 describes the Keep in Touch activity on Inertial Fusion.


1 PROVISION OF SUPPORT TO THE ADVANCEMENT OF THE ITER PHYSICS BASIS

1.1 DEVELOPMENT OF CANDIDATE OPERATING SCENARIOS

1.1.1 ELM PHYSICS AND CONTROL

1.1.1.1 ELM STUDIES IN JET WITH VISIBLE FAST CAMERA.

The visible intensified Fast Camera system installed in JET with ITER Like Wall was

used for ELM studies. Fast imaging of the dynamic of the ELM with up to 105 frames per second

reveal the formation of an emission region that seems to be in the far scrape-off layer above the

inner divertor target that dominates during the ELM and disappears in the inter-ELM period.

Further, the emission of beryllium from the walls and divertor with a Be II filter was

characterised and the speed of up to 5000 frames per second was achieved and validated to be

enough for future ELM impurity studies [JET_FastCamera delaCal]. A dedicated experiment for

C-31 campaign in 2013 is approved.

1.1.1.2 THE EFFECT OF ELM PACING VIA VERTICAL KICKS ON THE ACCESS TO STATIONARY H-MODE WITH GOOD CONFINEMENT (H98~1) ON JET

ITER is expected to operate at powers close to the H-mode threshold power scaling. This

might leave ITER with very little margin in terms of the available power flux crossing the

separatrix (~30% above the predicted H-mode threshold power as reported in [1]) to drive the

plasma into H-modes with normalized energy confinement time H98≥1, required to achieve Q=10 or higher. In the case of JET, such operation (with CFC wall) leads to a transient behaviour

of the H-mode, with transitions from very low frequency Type I ELMs (10-15 Hz) is critical to achieving robust

steady state H-mode operation with tolerable core W concentration, in line with the AUG results.

Experiments carried out at JET, before the installation of the ITER-like metallic wall (Be

wall and W divertor), have shown that effective ELM triggering via vertical kicks (fkick~10-20 Hz) can be achieved in H-mode plasmas at power levels marginally above the H-mode power

threshold, which provides sufficient degree of impurity content and radiation control to maintain

stationary conditions, with no additional penalty in terms of confinement. These results suggest

that the use vertical kicks may provide a potential route towards minimizing the W impurity

build-up during the early phase of the H-mode in ITER during current ramp up/down phases. A

major advantage of the vertical kicks with respect to the rest of the available ELM frequency

control methods is that the ELM frequency can be controlled without affecting any other plasma

parameter (no added impurities or density). Feasibility studies for ITER have shown that plasma

http://labfus.ciemat.es/AR/2012/CAP1/JET_FastCamera%20delaCal.pdf


vertical excursions similar to those obtained in JET at a maximum frequency of 20-30 Hz could

be delivered with the existing internal VS coil system during the current ramp up/down phase

(with Ip below 10 MA), which opens up the possibility of using vertical kicks as a tool for ELM frequency control in ITER. Nevertheless, extrapolation of the JET results to the ITER conditions

is difficult as long as the mechanism for the triggering of the ELMs is not better understood. On

this topic, a substantial progress has been made on the capability to model the underlying

physics involved in the kick-triggered ELM. The initial results of the simulations suggest that the

mechanism by which vertical kicks trigger ELMs is strongly linked to edge currents and their

effect on edge stability. We must, however, wait for the more accurate closed-coupled

simulations to confirm this hypothesis. A positive trend for the kick probability to trigger an ELM

with increasing edge Te is deduced from the modelling (at lower edge resistivity the induced edge current increases faster) and confirmed experimentally, which is encouraging in view of

ITER. Further modelling and experimental work are needed to improve the predictive capability

of a physics basis model of the ELM triggering mechanism via vertical kicks [JET_ELMs dela

Luna].

1.1.2 CONTRIBUTION TO JET RESULTS IN VIEW OF ITER OPERATION

In the last time, JET has been in operation with a programmatic focus on the

qualification of ITER operating scenarios, on the contribution to ITER design and the

preparation of for plasma confinement with the ITER-like Wall, which is being installed

presently. Good progress has been achieved, including stationary ELMy H-mode operation

at 4.5 MA and high triangularity. Particularly, Edge localized mode (ELM) control studies

using external n = 1 and n = 2 perturbation fields have been performed. Complete ELM

suppression has, however, not been observed, even with an edge Chirikov parameter

larger than 1 [Romanelli-NF].

1.3 ENERGY AND PARTICLE CONFINEMENT AND TRANSPORT

1.3.1 L-H PHYSICS

1.3.1.1 CHARACTERIZATION OF THE DYNAMICAL COUPLING BETWEEN FLOWS AND FLUCTUATIONS IN DIFFERENT MAGNETIC CONFIGURATIONS (Q SCAN) DURING THE L-H TRANSITION IN TJ-II.

In TJ-II experimental evidence supporting the central role of zonal flows has been

observed in experiments performed close to the L-H transition threshold conditions. A coupling

between flows and turbulence is found which reveals a characteristic predator-prey behaviour.

During the 2012 experimental campaign in TJ-II, dedicated experiments have been

carried out to investigate the spectral structure of the turbulence-flow interaction during the

predator- prey process. The comparison between maxima and minima of the density fluctuation

level measured during the intermediate oscillatory phase shows a rather well defined wave-

http://labfus.ciemat.es/AR/2012/CAP1/JET%20ELMs%20dela%20Luna.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/JET%20ELMs%20dela%20Luna.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/Romanelli-NF.pdf


number range, k⊥ ≈ 6 - 11 cm-1, where the oscillation in the turbulence level is maximum. At

shorter and longer turbulence scales, almost no oscillation in the turbulence level is detected.

These measurements indicate that the relevant turbulence scales involved in the energy

transfer of the predator-prey process are the intermediate ones, those at which the zonal flow

generation by Reynolds stress is more effective. These results were the central subject

discussed in the invited talk of the 2012 EPS Conference on Plasma Physics: EPS 2012 invited-

speakers and that in the 2012 IAEA Fusion Energy Conference FEC IAEA 2012; in addition the

results have been published in [PPCF_Estrada_2012]. These TJ-II experimental results on the

dynamical coupling of flows and turbulence have been the seed for the development of

theoretical models on the L-I-H transition [PoP_Miki_2012].

1.3.2 MOMENTUM TRANSPORT

1.3.2.2. DAMPING MECHANISMS OF FLOWS:

Report and measurements of plasma viscosity by studying the mass flow response to a

external force exerted by a biasing electrode in H / He plasmas to address the role of magnetic

viscosity and atomic friction (neutrals) on flows; comparison with neoclassical effects.

A series of experimental sessions were devoted to edge current modulation with

external biasing and simultaneous monitoring of edge floating potential. Several configurations

and plasma densities were studied and neoclassical estimates of radial resistivity (directly

related to poloidal viscosity) were obtained for comparison. While the analysis of the

experimental data obtained casted radial resistivity values in the range of those expected neo

classically (~ 20 - 40 Ohms/cm) for TJ-II, their radial dependence is strongly suggestive of the

presence of current losses in most of the exterior radial locations. This observation

recommends further, more interior biasing experiments in order to verify the validity of the

experimental procedure for the determination of the resistivity. These experiments have been

re-scheduled for the spring 2013 campaign.

1.3.2.3 DRIVING MECHANISMS OF ZONAL FLOWS:

Report on poloidal/radial characterization of long-range correlations, using 2-D probe

arrays and study of the role of radial-poloidal Reynolds stress on the development of long-range

correlations (zonal flows).

The dynamics of fluctuating electric field structures in the edge of the TJ-II stellarator,

that display zonal flow-like traits, were studied with a two dimensional array of probes. These

structures had been shown to be global and affect particle transport dynamically [Alo_NF12]. In

[Alo_PPCF13] we have continued the characterization of their dynamics by experimentally

inspecting Reynolds stress as a possible drive mechanism and neoclassical viscosity and

geodesic transfer as possible damping terms. We have shown that: (a) while the observed

turbulence-driven forces can provide the necessary perpendicular acceleration, a causal

relation could not be firmly established, possibly because of the locality of the Reynolds stress

http://epsicpp2012.spp.ee.kth.se/programme/invited-speakers/magnetic-confinement-fusion-plasmas/http://epsicpp2012.spp.ee.kth.se/programme/invited-speakers/magnetic-confinement-fusion-plasmas/http://fec2012.iaea.org/contributionDisplay.py?contribId=320&sessionId=28&confId=10http://labfus.ciemat.es/AR/2012/CAP1/PPCF_Estrada_2012.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/PoP_Miki_2012.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/Alo_NF12.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/Alo_PPCF13.pdf


measurements (which might not be representative of the flux-surface averaged turbulent force),

(b) the calculated neoclassical viscosity and damping times are comparable to the observed

zonal flow relaxation times, and (c) although an accompanying density modulation is observed

to be associated to the zonal flow, is not consistent with the excitation of pressure side-bands,

like those present in geodesic acoustic oscillations, caused by the compression of the E × B

flow field.

1.3.2.4 ELECTROMAGNETIC TURBULENCE AND MAXWELL STRESSES

The onset of the edge shear flow development has been investigated in TJ-II for

different plasma conditions. Two sets of Langmuir probes separated about 160º toroidally (more

than 5 m) and 150º poloidally one from the other, have been used to determine the Long-Range

Correlation. Close to the plasma transition to improved confinement regimes (ECRH low

density, Neutral Beam Injection high density or biased plasmas) bursts of long-range correlated

fluctuations have been observed. These low frequency oscillating structures (typically below 20

kHz) have been associated with Zonal Flows developed at the plasma edge.

Experimental results show the development of the edge-sheared flow concomitant with

the reduction in the amplitude of long-range correlations. Low frequency oscillations can be

observed before the development of the mean edge sheared flow.

The radial profile of the long-range correlation indicates the presence of fluctuating

evolving in time scales of milliseconds and modulating global transport are consistent with ZF

developed at the plasma edge when the plasma is closed to the low-density ECRH transition.

Reynolds stress has been measured using a bidimensional Langmuir probes system (5

poloidal rows x 4 radial columns). The electrostatic component of the Reynolds stress,

proportional to , has been computed considering the corresponding gradients of the

floating potential in the radial and poloidal direction to measure the radial and poloidal

fluctuating electric fields (i.e. neglecting electron temperature fluctuation effects).

In the TJ-II stellarator electromagnetic fluctuations are much stronger during ECH

phase than NBI phase, which is a surprising result. The presence of large populations of

suprathermal electrons (caused by the low density of such discharge phases) has been

proposed as an explanation.

Values of Reynolds and Maxwell tensors have been measured in the edge of the TJ-II

stellarator. When compared, Reynolds tensor has been found to dominate both in ECH and NBI

phases. The Reynolds tensor displays a clear radial dependence, with significant gradients in

the proximity of the edge shear layer in agreement with previous experiments. Interestingly, the

cancellation effect predicted in some theoretical predictions has not been observed.

1.3.3 IMPURITY TRANSPORT STUDIES

˜ E r ˜ E


1.3.3.1 SEE 3.1.3.1

1.3.4 ISOTOPE EFFECT

1.3.4.1 REPORT ON THE IMPACT OF THE ISOTOPIC EFFECT ON PLASMA CONFINEMENT (H / D) AND AMPLITUDE OF LONG-RANGE CORRELATIONS (ZONAL FLOWS)

Edge plasma potential and their fluctuations were simultaneously characterized in two

different toroidal / poloidal positions apart using multi-Langmuir probes in Hydrogen and

Deuterium plasmas in the TJ-II stellarator to study the influence of the isotope effect in the

amplitude of LRC of potential fluctuations in stellarator.

Experimental findings have shown that the LRC of potential fluctuations (i.e. the

amplitude of zonal flows) is, within the experimental uncertainties, constant during the transition

from H to D dominated plasmas in the TJ-II stellarator, in contrast with recent findings in the

TEXTOR tokamak. Interestingly the isotope effect seems to be weaker in stellarators than in

tokamaks. Thus, comparative studies in tokamak and stellarator provide a guideline for further

studies of the impact of multi-scale physics to unravel the physics of the isotope effect in fusion

plasmas

1.4 MHD STABILITY AND PLASMA CONTROL

1.4.1 ELM PHYSICS

1.4.1.1 ELECTROMAGNETIC TURBULENT STRUCTURES

Electromagnetic features of turbulent filaments, emerging from turbulent background,

have been studied in three different magnetic configurations: the stellarator TJ-II, the Reversed

Field Pinch RFX-mod and the Simple Magnetized Torus TORPEX. By applying an analogous

diagnostic concept in all cases, direct measurements of both field-aligned current density and

vorticity were performed inside the filament. The inter-machine comparison revealed a clear

dependence of the filament vorticity upon the local time averaged E x B flow shear.

Furthermore, a wide range of local beta was explored allowing concluding that this parameter

plays a fundamental role in the appearance of filament electromagnetic features.

1.4.1.2 DETERMINATION OF PLASMA STABILITY USING RESONANT FIELD AMPLIFICATION IN JET

We have contributed to the study of the effect of Resonant Field Amplification (RFA) on

plasma stability in JET. Reduction in RFA is observed during an outer mode for the first time.

RFA has been systematically measured on JET, using active MHD spectroscopy to probe

plasma stability at high and low beta, and compared with theoretical predictions. RFA has been

measured as a plasma response to externally applied fields. Current density and q profiles have found theoretically and experimentally to influence beta limit strongly. At low beta, RFA has

been analysed in detail during edge-localized mode (ELM)-free periods prior to the first ELM


either after L–H transition or after long ELM-free periods during a pulse. These observations

confirm that the measured increase in the RFA in some cases (e.g. at low beta) may reflect a

proximity to stability thresholds, different from the no-wall beta limit associated with the RWM.

The first results on n = 2 probing on JET are presented [Gryaznevich_NF_2012].

1.4.2 PLASMA CONTROL

Work on plasma internal inductance control in tokamaks using electromagnetic

induction [(1_3_2_1), (1_3_2_2), (1_3_2_3)] has continued to incorporate new observers for

plasma inductance and plasma geometry based on current tomography methods, which involve

only linear operations and are then most suitable for real time implementation. These observers

have been validated with actual TCV tokamak data and they have also been used to perform

magnetic sensor optimization studies [(1_3_2_4)]. The design work is now moving towards the

simultaneous control of plasma current and inductance using just the electromagnetic induction

available from the tokamak transformer (under-actuated system).

New robust control designs based on sliding mode control methodology have been

performed using a model valid for the JET tokamak, testing the performance with numerical

simulations [(1_3_2_5)].

A new Rogoswki coil sensor has been installed in the TJ-II stellarator in view of a future

plasma current control system that would extend the present functionality of the magnetic

configuration sweeping capability.

1.5 POWER AND PARTICLE EXHAUST. PLASMA-WALL INTERACTION

1.5.1 DEPOSITION IN GAPS AND THERMO-OXIDATION BY NO2

A new setup was used to investigate the deposition of eroded carbon at the

bottom of the 1mm gaps with depths from 5 to 20 mm. Toroidal and poloidal transport was

investigated by exposing a graphite bar to the plasma. Two levels of insertion led to a strong

change of sample temperature, allowing for the discrimination between chemically sputtered (at

high T) and physical sputtered sources. AES and SIMS were used to characterize the deposits

in the gap at the JSI in Liubliana. While physical sputtering leads to line-of-sight transport,

dominated by simple geometrical constrains, chemically eroded carbon produces a much

broader pattern.

Experiments have been carried out in collaboration with the Toronto UTIAS team for the

thermo-oxidation of carbon tiles from DIII-D by NO2 and its comparison with more conventional

O2 at several temperatures and pressures. Measurements of D contents by LID, NRA and mass

spectrometry were addressed [NO2 PSI-12]. No clear evidence of water formation during the

removal of the co-deposits by oxidation by NO2 has been found yet. The enhancement in the

removal rate of C and D observed in Ciemat when O2 is replaced by NO2 was confirmed by the

Toronto group, but the situation seems to revert at high temperatures (400º), perhaps due to the

decomposition of NO2 in hot elements.

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1.5.2 ACTIVITIES ORIENTED TO THE VALIDATION OF LI AS A PFC FOR A FUSION REACTOR

Several experiments about the compatibility of lithium elements with a hot plasma were

carried out during 2012. First, the lithium liquid limiter (LLL) was exposed to the plasma at

several temperatures (up to 400ºC) and degrees of insertion into the plasma (up to 3 cm inside

the SOL) with good performance. In addition, a lithium bar (solid) was inserted at several levels

and the I/V characteristics were recorded. Emission of Li and Li+ were also recorded near the

bar, providing evidence of self-protection by development of a dense plasma near the bar [(Li-

1), (Li-2), (Li-3)].

1.5.3 REDUCTION OF THE SPUTTERING YIELD OF W BY IN-SITU NITRIDING

Several methods were used for the formation of a WN layer on W samples, included

plasma- assisted techniques in the MHEST association, Romania, like reactive sputtering and

magnetron sputtering with several degrees of mixing W/N interlayer mixing and thickness.

However, SIMS analysis indicates that only a very thin (2nm) layer is produced by exposing W

samples to a N/He GD. Also, N seeded discharges were performed in JET under the new ILW

scenario, and some evidence of ammonia formation was seen through the de-convolution of the

mass spectra, with obvious implications in the particle balance analysis of D and N [JET PSI-

12]. Samples from MHEST were exposed to Magnum PSI at DIFFER and a strong erosion,

although compatible with at reported for the sputtering yield of WN2, was observed [WN-1]

1.5.4 EDGE TRANSPORT AND PARTICLE AND IMPURITY SOURCE

1.5.4.1 RADIAL PLASMA TRANSPORT AND RECYCLING OF NEUTRALS.

The helium ratio technique applied with the "Double Imaging technique" (see point

2.2.1.9) has permitted to obtain 2 dimensional images of electron temperature and density in

TJ-II edge plasmas with temporal resolution of about 50 µs. Using the emission I from one of

the recorded He I lines (667 nm), that is relatively insensitive to the electron temperature in the

typical operational range of TJ-II NBI heated plasmas (20 < Te < 100 eV) we can obtain in a

first approximation the neutral helium density distribution as nHe I / ne. Comparison of the so-

obtained radial nHe profiles with EIRENE calculations are in good agreement. We apply this

method to get the nHe dynamic response low frequency edge modes and get a full dynamic 2

dimensional picture of the plasma radial out-flux showing the Te, ne crash and the nHe

instantaneous wall-recycling response. The study is underway and will be concluded in 2013.

1.6 PHYSICS OF PLASMA HEATING AND CURRENT DRIVE

1.6.1 DEPENDENCE OF PLASMA FLUCTUATIONS ON RF STRAY RADIATION

A lot of work has been devoted to the improvement of the RF stray radiation detection

system. At present, all the stray radiation monitors ECA1, ECA2, ECA4, ECA5, which work in

http://labfus.ciemat.es/AR/2012/CAP1/Li-1.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/Li-1.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/Li-2.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/Li-3.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/JET%20PSI-12.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/JET%20PSI-12.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/WN-1.pdf


the WR19 band and ECA3, ECA6, ECA7 as well as the two detectors connected to the sniffer

probe, working in the WR28 band, are absolutely calibrated detectors. By using fixed

attenuators, we ensure that all the diodes are working in an approximately linear regime.

Once the polarization capabilities were checked, measured and proved to be consistent

with the theoretical predictions [ECRH1], the experiments on the relation between plasma

fluctuations and RF stray radiation, controlled by mismatching the wave polarization, were

carried out. These experiments are proposed within the framework of the EFDA task WP11-HCD-01-03-01 (Real-time polarization control for ITER EC system). The analysis of the results is still in progress. 1.6 Energetic particle physics

1.7 ENERGETIC PARTICLE PHYSICS

1.7.1 FAST ION STUDIES.

The workflow established between ISDEP and FAFNER2 codes allows one to perform

kinetic simulation of fast ion transport in magnetic coinfinement device. Calculations for the TJ-II

stellarator has been performed in order to elucidate the properties of fast ion confinement in

such device [bustos2]. The results of these simulations were compared to experimental

measurements for TJ-II discharges finding a good agreement both in he spectra and in the fast

ion flux [bustos3]. So, we consider that these calculations are vaidated and these two codes can

be used together to estimate collsional fast ion transport in fusion devices. The deviation of the

experimental data from these calculations will be due to anomalous and Alfvén wave induced

transport.

1.7.2 ALFVÉN EIGENMODE PROPERTIES

The characterization of the Alfven eigenmodes (AEs) measured in NBI plasmas has

progressed, taking advantage of the HIBP diagnostic [20120404_NF].

A joint experiment in TJ-II and Heliotron J (Kyoto University), both low-shear devices

but with substantiallly different rotational transform has allowed the comparison between the

AEs observed in both machines. The result of this study suggests that global AEs are unstable

in both low-shear configurations independently of their iota value. However, helicity-induced

AEs become destabilized only in the high-iota TJ-II configuration. These results have been

presented in the 10th Stellarator/Heliotron Coordinated Working Group meeting (Greifswald, 6-8

June 2012) [20120604_CWGM10] and in the IAEA-Fusion Energy Conference in san Diego, CA

in October [20120926_IAEA_FEC]

1.7.3 EFFECT OF ECH APPLICATION ON ALFVÉN EIGENMODES ACTIVITY

New joint experiments on energetic particle physics involving researchers from

CIEMAT, NIFS, Kyoto University and Kurchatov Institute (Moscow) have been conducted in TJ-

II in March 2012. The emphasis this year has been focused on the effect of the ECH application

on the AE activity. The results obtained show that, upon ECH application with moderate power,

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the continuous character of the AEs becomes altered and displays frequency chirping. If the

ECH power is further increased the AE can be eventually stabilised. This result suggests a

possible tool for AE control that, if confirmed, could become ITER and reactor-relevant.

Preliminary presentations were made at the ITPA Energetic Particles Topical Group meeting in

La Jolla, in October [20121015_ITPA_EP] and in the 22nd Toki Conference in November

[20121119_ITC22].

1.8 THEORY AND MODELLING FOR ITER AND DEMO

1.8.1 PLASMA HEATING (NBI)

The last versión of ISDEP (Integrator of Stochastic Differential Equations for Plasmas)

code has been combined with to estimate the properties of fast ion collsional transport in ITER.

First results on the fast ion distribution function and on slowing down times are available

[bustos-thesis].

1.8.2 COMPUTATIONAL DEVELOPMENTS

Grid computing

The activities on grid computing and on the development of tools to improve the

performance of fusión code have been continued. We have implemented the technique of “Pilot

Jobs” to improve the efficiency of DKES codeo n the grid [Rubio-IEEE-2012], obtaining a huge

capability for scanning the Neoclassical properties of several TJ-II configurations: running the

code using the Pilots under the metascheduler Gridway allows to launch a huge number of Jobs

in a coordinated way.

Workflow Building

The workflow FAFNER2-ISDEP has been built and applied to fast ion calculations. This

happens to be sequential workflow, so no especial tool has been used for its implementation:

The ISDEP code has been prepared to read the output of FAFNER, which hs been adpated to

ITER geometry. First results of fast ions transport were extracted [bustos-thesis].

Moreover, Kepeler Workflow engine has been used to build heterogeneous workflows

among codes that runo n different computing platfroms, as a proof of concept a combination of

the codes VMEC, for equilibrium calculations, and DKES, which estimates the Neoclassical

transport coefcients, is used [proc-ieee-2012-WFs].

http://labfus.ciemat.es/AR/2012/CAP1/20121015_ITPA_EP.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/20121119_ITC22.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/thesis-bustos.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/bustos-thesis.pdfhttp://labfus.ciemat.es/AR/2012/CAP1/proc-ieee-2012-WFs.pdf


2 DEVELOPMENT OF PLASMA AUXILIARY SYSTEMS

2.1 HEATING AND CURRENT DRIVE SYSTEMS

2.1.1 ELECTRON BERNSTEIN WAVES HEATING EXPERIMENTS IN TJ-II

Full redesign of the matching optics unit (MOU): Discussions with GYCOM about the

waveguide coupling problem eventually led to the following conclusion: the beam distortion

effects, i.e. aberrations and production of higher order modes, generated by the large mirror

size (due in turn to the large size of the MOU itself) prevented the proper coupling to the HE11

mode at the waveguide mouth. A more compact design was undertaken in October 2012 in

order to minimize the beam distortion effects. The new design of the MOU makes it necessary

to move the gyrotron to a position closest to the waveguide. EBWH Experiments will be

resumed during the first half of 2013.

2.1.2 NBI HEATING STUDIES: ION TRAJECTORY CALCULATION

Ion trajectory calculation: A realistic assessment of beam power losses due to

reionization is necessary for the correct interpretation of the plasma-beam interaction.

Reionization losses are particularly important in the beam duct connecting the beamline with the

stellarator vacuum vessel. Ion trajectories must be evaluated, since the impact areas in the duct

or vacuum chamber are a source of gas and impurities and must be protected from potentially

high thermal loads.

An ion trajectory code has been written (TRAYN) that follows the trajectories of ions in

the residual magnetic field of TJ-II from their birth point inside the NBI duct until they hit the wall,

either in the duct or in TJ-II vessel. For the main ion energy (34 keV) and the magnetic field

range in the duct region (0.01 to 0.25 T), the center-guide approximation is not valid; therefore a

finite Larmor radius approach has been implemented. A statistical approach has been followed,

in that the ion birth points are uniformly distributed on perpendicular planes along the beam

axis. No assumption has been made on the distribution of birth points along the duct, since this

distribution depends on the pressure profile which in turn depends on the gas re-emission areas

inside the duct, where the hot spots due to ion striking points are located. The statistical results

permit the ion birth region to be inferred from comparison with the observed hot spots on the

infrared images [Semin_Reion_TRAYN_120127].

2.1.3 ECH ACTIVITIES IN TJ-II

2.1.3.1 CHANGES IN THE GYROTRON RADIATION PROPERTIES, INDUCED BY A SMALL AMOUNT OF REFLECTED MODULATED POWER.

The basis for these experiments is the hypothesis that a low fraction of the gyrotron

emitted power, which is reflected back to its source, can strongly modify the gyrotron behaviour

and produce a reaction on the output radiation depending on the phase of the reflected wave.

Using a quasioptical divider, it has been demonstrated that the gyrotron radiation is indeed

http://labfus.ciemat.es/AR/2012/CAP2/Semin_Reion_TRAYN_120127.pdf


modulated by reaction to the reflected modulated power under controlled conditions and that the

strongest influence in seen in the beam periphery. Regular measurements with plasma were

carried out during the 2012 campaign and the results are still under analysis. This work has

been carried out in collaboration with the Institute of Applied Physics (Russian Academy of

Science), Moscow and Nizhny Novgorod (Russia).

2.1.3.2 SECOND HARMONIC X MODE BREAKDOWN EXPERIMENTS.

To complete the breakdown experiments carried out in previous campaigns the

influence of the delay between the build-up of the plasma discharge and the flat-top of the

currents in the device coils was investigated. The results of the experiments are summarized in

[ECRH2].

2.2 PLASMA DIAGNOSTICS

2.2.1 DEVELOPMENT OF PLASMA DIAGNOSTICS IN TJ-II

2.2.1.1. CALIBRATION OF THE MULTI-FOIL SOFT X-RAY DIAGNOSTIC (M4F) FOR CORE ELECTRON TEMPERATURE ESTIMATIONS.

First-order approximation (i.e. by using fixed standard electron density and temperature profile shapes) of the central electron temperatures (Te0) estimated by the M4F diagnostic has

been benchmarked with the Thomson Scattering diagnostic. This has been done for plasmas

with different magnetic configurations, densities, NBI power inputs and plasma compositions.

The agreement is very good in all cases except when the NB counter-injector was used. This

discrepancy was attributed to the presence of metals in the plasma as a consequence of a

strong interaction of this beam with the vacuum vessel. When iron was included in the

calculations, the agreement with Thomson was re-established. Second-order Te0 was also

obtained by using the reconstructed SXR and total radiation emissivity profiles (SXR and

bolometer tomography diagnostics) as a proxy to estimate the evolution of the electron density

and temperature profile shapes. This way, the temporal evolution of Te0 can now be reliably

obtained even for the case of strong plasma profile changes, as is the case of plasmas with

transitions from bell to dome profiles and/or L/H transitions [M4F].

2.2.1.2 ION TEMPERATURE MEASUREMENTS BASED ON ATOMIC BEAM MEASUREMENTS AND RFA DIAGNOSTIC DEVELOPED BY IST.

An upgraded RFA diagnostic system has been constructed by the IST Team during

2012. It will be installed in the reciprocating probe drive, located at a high flux expansion region

to reduce the plasma heat flux to the diagnostic. Experiments are planned for the 2013 TJ-II

campaign. Benchmarking with the atomic He-beam

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2.2.1.3 COMMISSIONING OF SECOND HIBP INJECTOR / ANALYZER FOR ZONAL FLOW STUDIES IN TJ-II. (CAPITAL EXPENDITURE EXCLUDED UNLESS INCLUDED IN EFDA TASK AGREEMENTS)

This project is the result of a big collaboration of Kharkov Institute, kurchatov institute

and Ciemat. The second line of heavy ion probe in TJII was installed and the whole system was

checked successfully including: new control and data acquisition system based on ITER

compatible PXI modules and Lab View software, Ciemat workshop built ion detectors, and

Ciemat electronics team produces preamplifiers, optocouplers, all of these components are

installed and working. The actual bandwidth of the system is 500 kHz (3dB).

The first test has been made and we obtain a current of 60 μA of Cs ions with a filament

current of 12 A DC.

We expect to find secondary ions before the end of June during the first 2013 TJII

experimental campaign.

The commissioning of the second HIBP will be held before the end of 2013.

2.2.1.4 DEVELOPMENT OF A PELLET INJECTOR FOR TJ-II

The construction of the compact 4-barrel pellet injector (PI) for the TJ-II was completed

during 2012 at Oak Ridge National Laboratory, Oak Ridge, Tennessee (where the main

hardware PI was built). In parallel, the preparation work for its installation continued at TJ-II.

Laboratory testing of the system, i.e. production of pellets at 10 K and subsequent firing of the

solid pellets, was undertaken in March 2012 at ORNL [Combs1]. During testing, hydrogen

pellets with diameters between 0.5 and 1 mm were created and fired. In addition, local

diagnostics for measuring the speed, mass and form of the pellets were demonstrated to

operate correctly. Once testing had been completed, the interface coupling required to attach

the PI to TJ-II, was designed and built at ORNL. Finally, the PI was packed and shipped to

Ciemat, where it was arrived in August 2012. Over the following months, the PI was installed on

its support structure, designed and built at Ciemat, and the control electronics were installed in

an electrical cabinet. In addition, systems such as gas manifolds, vacuum pumps, pressure

transducers and gas storage cylinders, were fitted to, and tested on, the PI. Finally, the cryo-

refrigerator, essential for achieving 10 K, was installed and checked. In March 2013, the PI

system was cooled to 10 K for the first time at Ciemat. It is expected that the commissioning of

the PI will be completed at Ciemat once the remote control system has been installed and

tested. Once demonstrated, the first pellets can be created and injection of pellets in TJ-II

plasmas can begin.

2.2.1.5. THE DIAGNOSTIC NEUTRAL BEAM INJECTOR AND ASSOCIATED INSTRUMENTATION

Studies on TJ-II plasmas using the Charge Exchange Recombination

Spectroscopy technique continued during 2012. This diagnostic views the plasma minor radius

http://labfus.ciemat.es/AR/2012/CAP2/Combs1.pdf


from 36 top, bottom and toroidal lines-of-sight. In particular these studies concentrated on fully-

ionized carbon ion flows in ECRH and NBI plasmas. In the first instance, it was demonstrated

that flow measurements, performed at different locations of the same flux surface, are

compatible with flow incompressibility for low-density plasmas (line averaged electron densities

≤1019 m-3). Furthermore, comparison with neoclassical calculations showed quantitative

agreement with measured radial electric field and ion parallel mass flow in the absence of an

external momentum input. For the case of higher density plasmas, in surface variations of this

velocity were observed systematically, thus pointing to a breakdown of impurity flow

incompressibility at densities above 2x1019 m-3 [Arevalo1].

In order to maximize the scientific return of both the TJ-II diagnostic neutral

beam and its associated optics, studies were made using beam emission spectroscopy (BES)

from a tangentially viewing port in sector B1. In a previous report, the viability of performing BES

on TJ-II was demonstrated. For these studies, the DNBI neutral beam has been employed

together with a 12-way fibre bundle, a narrowband filter centred on 659.6 nm, with a Full-Width

at Half-Maximum bandwidth of = 1 nm, and 6 avalanche photodiode modules, with high

sensitivity (around 650 nm) and internal gain plus frequency response up to 1 MHz. The results

of these studies, where localized modes were observed at specific radius of the TJ-II plasma

were reported at the XXIII Reunión Nacional de Espectroscopía VII Congreso Ibérico de

Espectroscopía in Cordoba, 2012 [McCarthy1]. In addition, the results were present in a Master

Thesis for the Joint European Master in Nuclear Fusion Science and Engineering Physics, at

Ghent University [Achkasov1].

2.2.1.6 DOPPLER REFLECTOMETRY SYSTEM

Design and construction of a new Doppler reflectometer

The construction of the new Doppler reflectometer in the 50-75 GHz frequency band,

done in collaboration with the IST Microwave Reflectometry Team, was finished during the first

part of 2012, and its installation in TJ-II was implemented at the end of the first experimental

campaign, in July. The system was tested and calibrated after the installation and started

operation in the second experimental campaign in autumn. Band rejection filters have been

designed and developed in collaboration with the Universidad Politécnica de Madrid to protect

the new system against the high power of the gyrotrons used to heat the plasma. They are the

subject of a publication in Fusion Engineering and Design [FED_Montejo_2012]. During 2012 a

new approach to detect coherent modes using microwave reflectometry was developed. The

approach is based on the modulation of the reflecting layer in the poloidal direction due to the

presence of rotating coherent MHD modes. The applicability of the approach was

demonstrated, using either conventional or Doppler reflectometry, in plasmas with a high

background turbulence level where the standard analysis method fails. These results, have

been published in [NF_Estrada_2012]; it is worth mentioning that this article has been selected

by the Nuclear Fusion.

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2.2.1.7. STUDIES ON DOUBLE PULSE THOMSON SCATTERING MEASUREMENTS

The diagnostic has provided during 2012 in a regular way electron temperature (Te) and electron density profiles (ne) for TJ-II discharge documentation & physics studies.

The new Power Supply Unit (PSU), built by the laser company (INNOLAS, Rugby, UK)

and delivered to CIEMAT in late 2010 has continued to be used intensively and with very

satisfactory results during the 2012 TJ-II plasma campaigns. The purchase of the new Power

Supply has been partially supported under Project ENE2009-10181, leaded by Dr. María

Antonia Ochando, CIEMAT. Following the successful proof-of-principle test of double pulse

Thomson Scattering shots made in the 2011 spring campaign, preliminary contacts with the

laser builder (INNOLAS UK) have been maintained so as to ask for the possibility of installing in

the laser a third amplifier, so as to raise its energy to the 20 J level (single pulse) or 10-10 J in

double pulse operation. This upgrade will increase diagnostic performance in particular when

measuring moderate-density ECRH heated plasmas. A quote has been received, estimating the

upgrade in the order of € 75,000. More studies are needed in order to evaluate the

costs/benefits of the proposed upgrade.

Software (SUN workstation) and Hardware (ruby laser) maintenance policies, which

have been shown to be operative in previous years, have been continued during 2012. During

2012 nevertheless, the main focus of the TS system has continued to be in providing Te and ne profiles in single shot operation.

The Thomson Scattering group in-kind collaboration (with Dr. R.F. Álvarez-Estrada,

UCM, and Drs. J. Guasp and F. Castejón, CIEMAT) in theoretical/numerical relativistic

Thomson Scattering (ITER oriented) has continued during 2012, extending and generalizing

previously obtained results so as to be able to compute in a purely analytical way the Thomson

Scattering spectrum coming from nearly arbitrary electron distribution functions. In particular, a

systematic exploration of the Thomson Scattering spectrum arising from non-Maxwellian or

anisotropic electron distribution functions has been carried out and the results have been

published in [NF_Pastor_2012] and [PoP_Alvarez_Estrada_2012]. It is worth mentioning that

the first article has been selected by the Nuclear Fusion Editors as part of the NF Highlights

2012

2.2.1.8. NPA UPGRADING

During the 2012 year, the NPA top diagnostic was upgraded from 6 channels in H row

to 12 channels in H row. The operation included the manufacturing of some pieces in the

workshop, the assembly of the new detector’s row in the NPA and then the sending to Ioffe

Institute in Saint Petersburg (Russia) for the calibration. Once calibrated was returned to the

laboratory were it was installed in its position and tested with the participation of two scientists

from Ioffe Institute.

On the other hand, the DOUBLE code was adapted to work with TJ-II plasmas. It is a

code developed in Ioffe Institute to simulate the flux arriving to the neutral particle analyzer. This

http://labfus.ciemat.es/AR/2012/CAP2/NF_Pastor_2012.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/PoP_Alvarez_Estrada_2012.pdfhttp://iopscience.iop.org/0029-5515/page/highlights-2012http://iopscience.iop.org/0029-5515/page/highlights-2012


code was adapted to the geometry and plasma parameters of TJ-II and the result of the

simulation agrees the experimental data [NPA1].

The results of the code have been used to improve the calculation of the main ion

temperature of the plasma, giving a correction of about 15% higher in both heating schemes,

ECRH and NBI plasmas.

2.2.1.9 TWO-DIMENSIONAL IMAGING OF EDGE PLASMA ELECTRON DENSITY AND TEMPERATURE.

A system was developed and validated in the past to image the electron temperature

and density at the plasma edge applying the helium line ratio technique with a fast camera. The

method is being applied in TJ-II to analyze spatially coherent structures such as Edge Modes

and Blobs. The time resolution is in the 10 ms range. Edge modes have a temporal quasi-

coherent character in certain NBI heated regimes and begin with a flattening of the electron

density profile near r/a = 0.75 and is followed by an outward heat pulse with a speed of typically

100 m/s. On the other hand, the electron density of coherent turbulent structures (in the

centimetre range) called blobs and holes are up to +/- 1x1018 m-3 corresponding to variations of

up to +/-100% of the mean value at the plasma last closed flux surface.

2.2.1.10 INVESTIGATION OF NON-THERMAL ELECTRONS IN THE BOUNDARY REGION OF THE TJII STELLARATOR FROM I-V LANGMUIR PROBE CHARACTERISTICS

Langmuir probes are one of the most common diagnostic tools to measure edge

plasma parameters with sufficiently high temporal and spatial resolution. In non-magnetized,

low density plasmas Langmuir probes allow local measurements of the plasma potential, the

charged particles density and the electron energy distribution functions (EEDF). In magnetized

plasma, the interpretation of current-voltage (I-V) characteristics is not straightforward above the

floating potential (i.e. the electron part of the IV characteristic is distorted due to the influence of

the magnetic field). Using the electron branch of a Langmuir probe I-V characteristic it has

been shown the presence of a small fraction of supra-thermal electrons together with a

dominant Maxwellian distribution in ECRH plasmas whereas in high-density NBI regimes the

electron distribution function is Maxwellian.

2.2.1.11. LINEAR ARRAY FOR ELECTRON TEMPERATURE MEASUREMENTS (M4FA)

After more thorough simulations of the signals observed in the already mounted

diagnostic it was decided that, as the signal levels were high enough, it would be better to

dismount the diagnostic to install new narrower collimators to increase the spatial resolution. At

the same time one of the channels was repaired and the in-vacuum amplifiers were substituted

by a new set of amplifiers, recently developed by the group of Electronics of CIEMAT. The new

amplifiers have a better temporal resolution (up to 10µsec), lower intrinsic noise and much lower

cross talk between adjacent channels. First light was obtained at the end of the last campaign

http://labfus.ciemat.es/AR/2012/CAP2/npa_1.pdf


and at the present time the analysis of the data in underway to produce the first electron

temperature profiles [M4FA].

2.2.2 DIAGNOSTIC EXPLOITATION AND DEVELOPMENT IN JET

2.2.2.1 COMMISSIONING AND MEASUREMENTS OF INTENSIFIED FAST VISIBLE CAMERAS FOR PLASMA-WALL STUDIES IN JET

After the successful installation of "test image intensifier" (on loan from CIEMAT) and

the extensive testing during the campaign JET decides that Image Intensifier will be helpful.

Procurement of a new image intensifier (following the decision taken at the DSW+ Diagnostics

package Project Board of 23.07.12). This procurement was made in 2012 and we

commissioned the new Image Intensifier at Ciemat in December 2012. In December 2012 we

start the absolute calibration of the system at JET, and in the next months we plan to obtain

quantitative data from the fast camera images, this calibration will be finalized in 2013.

We are starting to work in the correction of the rotation of the image due to the

combination of magnetic fields and first stage of amplification of the Image Intensifier, following

two different approximations, in collaboration with MeDC Association. For this topic, Ciemat

starts to develop a procedure to realize the software correction of the translational and/or

rotational movements experimented by the KL8A images using an automatic registration

algorithm with corresponding point position prediction. Assuming a rigid rotation/displacement

model, a transformation matrix, which determines how the input image must be transformed in

order to be aligned with the base image, is computed. First results were promising.

The project FC7-2phase is planned to be handed over and closed at the end of

September 2013 when the Final Report is approved.

2.2.3 DEVELOPMENT OF PLASMA DIAGNOSTICS IN W7X: IR INTERFEROMETRY

2.2.3.1 DEVELOPMENT OF A MODULAR SYSTEM OF CO2 INTERFEROMETER DIAGNOSTIC

Several basic works have been done. As it has been reported previously, the two-colour

interferometer of TJ-II has been operating using CO2 laser (10.591 µm wavelength) and NdYAG

(1.064 µm), instead of the previously used He-Ne (0.633 µm), because the ZnSe windows

thermo-optical dispersive effect is about 10 times lower for the NdYAG wavelength. It was

known that the arms of an interferometer using He-Ne lasers can be unequal; fact that permits a

substantial engineering simplification in the modular design because many mirror components

can be eliminated. Now, we have proved experimentally that also when using a NdYAG laser

the interferometer can have very different arm lengths (almost 10 meters). This is interesting

because the laser type, Solid State Diode Pumped laser is very different to the He-Ne. The

actual stabilized laser has enough coherence length to permit this asymmetry, maintaining the

http://labfus.ciemat.es/AR/2012/CAP2/M4FA.pdf


previous noise level. The asymmetric modular system is smaller and simpler than the symmetric

one and the alignment procedure is notably easier.

Also, the thermal stability in lasers with controlled temperature has been studied for

different water chillers.

Finally, the new phase-meter based in FPGA has been implemented and tried

2.2.4 DIAGNOSTIC DEVELOPMENT IN ITER

2.2.4.1 REFLECTOMETRY

The extrapolation of present day microwave reflectometry systems to future devices like

ITER is possible but, in order to achieve a good diagnostic performance, special care must be

taken in the diagnostic front-end design and construction. The main limitations related to

relativistic effects, intense neutron- and γ-radiation and long pulse or steady-state operation

have been reviewed and published as an Overview Article in [PFR_Estrada_2012].

In 2012, the consortium comprised of CIEMAT, IST and IFP-CNR was selected for the

award of the Framework Partnership Agreement for Diagnostic Development and Design, F4E-

FPA-375 (DG): Plasma Position Reflectometer. As specified in the FPA-375 Proposal

elaborated by the Consortium to apply to the F4E-FPA call, the FPA concerns the supply of

R&D and design related to the ITER Plasma Position Reflectometer and consist of a number of

Specific Grants between F4E and the Consortium partners. In particular CIEMAT will have full

responsibility of three of these Grants and will participate in another two, the first one dealing

with the Detailed Planning of the whole project and therefore of the subsequent Grants and the

second one being the Coordination Office.

2.2.4.2 VISIBLE – IR WIDE ANGLE VIEWING SYSTEM:CONSORTIUM CEA / CIEMAT / ENEA / HAS / IST

The Consortium comprised of Commissariat à l'énergie atomique et aux énergies

alternatives (CEA) and Centro de lnvestigaciones Energéticas, Medioambientales y

Tecnológicas (CIEMAT) has been selected for the award of the Framework Partnership

Agreement for Diagnostic Development and Design of Equatorial Visible/lnfrared Wide Angle

Viewing System for ITER.

2.2.4.3 THOMSON SCATTERING

Keep-in-touch activities of the Thomson Scattering Group in TJ-II with the Consortium

to build the Thomson Scattering system for ITER have been maintained during 2012. The scope

of possible Thomson Scattering designs for ITER has been widened from the previous (LIDAR)

design, due to the challenges posed by a LIDAR system to the existing laser and/or detector

technology. CIEMAT’s contribution will continue to be focused on the theoretical/numerical

aspects of the relativistic laser/electron interaction relevant for Thomson Scattering in very high

http://labfus.ciemat.es/AR/2012/CAP2/PFR_Estrada_2012.pdf


temperature plasmas, and on calibration techniques suitable for the final design adopted by the

Consortium partners.

2.2.5 REFLECTOMETRY SIMULATIONS

2.2.5.1 REFLECTOMETRY SIMULATIONS: DEVELOPMENT OF A 3D FULL-WAVE CODE RELEVANT FOR ITER.

A three dimensional (3D) simplified kernel was developed during 2010 and 2011 by the

Reflectometry Code Consortium. The kernel has the essential algorithm’s difficulties found in a

complete 3D modelling but absorbing boundary conditions, launching and receiving antenna,

plasma turbulence, etc. were intentionally omitted. During the 2012 most of the work has been

focussed in the implementation of the launching/receiving module and in the implementation of

the absorbing boundary conditions. These two upgrades have been integrated into the spatial

parallel scheme of the simplified 3D kernel with partial success. In particular, we have tested

the power injection module and some bugs were found in the code. It was found that the

emitted power was not completely uni-directional resulting in some microwave power of about -

20 dB being reflected back from the emitting plane. The source of this error still requires more

time and tests to be fully identified. It seems to be related to the external applied field to the

computational grid and its phase all along the emitting plane. In addition, the absorbing

boundary conditions (PML) were found to be working properly with some minor problems in the

corners of the computational domain. The effect in the received microwave power was

estimated to be not very important and the correction of this bug was delayed for a later revision

of the code.

Results:

a. Signal injection and detection modules have been implemented into the present

kernel version. More work is needed to remove some minor bugs found in the code.

b. Absorbing boundary conditions have been implemented.

c. Test of the new version of the code started in 2012.

Outstanding issues:

d. Improve antenna-vacuum-plasma propagation time by means of Green's functions or

equivalent algorithms.

e. Introduce plasma turbulence with high turbulence levels to test code stability in 3D.

f. Improve computational time by means of optimum communication and data transfer

between processors.

2.2.6 ADVANCED DATA ANALYSIS TECHNIQUES

This section includes different subsections related to the research on advanced data

analysis techniques on several topics: disruption prediction (except the activities related to the


JET real-time prediction that are included in section 2.4.2), L/H transitions, image processing

and miscellanea.

2.2.6.1 DISRUPTION PREDICTION

As it was mentioned above, this part does not include the works about disruption

predictions carried out on the JET real-time data network. However, with regard to JET, it is

important to point out a research article concerning automatic feature selection for disruption

predictors based on genetic algorithms [ADA_1]. Following with JET predictions, a poster

contribution was presented at the 27th SOFT Symposium (September 2012) whose novelty is

the proposal of an automated classification system that relies on the probability distribution of

frequencies in several indicator signals in the wavelet domain. The system discriminates

between disruptive and non-disruptive plasma behaviour by measuring the geodesic distance

between the wavelet distributions on the corresponding probabilistic manifold [ADA_2].

Also related to JET disruptions, a new prediction method was proposed in the 7th

Workshop on Fusion Data Processing Validation and Analysis (March 2012). A particular

classification methodology was discussed by using wavelet statistical features in conjunction

with geodesic distances on a manifold [ADA_3]. The work was applied not only to disruption

prediction but also to confinement regime identification [ADA_4] with the ITPA Global H-mode

Confinement Database.

2.2.6.2 CONFINEMENT TRANSITIONS

During 2012, this topic has been investigated with several databases and different

techniques. In addition to the results obtained with the ITPA Global H-mode Confinement

Database presented in section 2.2.6.1 [ADA_3] and [ADA_4], a technique based on conformal

predictors [ADA_5] was presented at the International Conference “Artificial Intelligence

Applications and Innovations” (September 2012). The measurements are modelled by

probability distributions in a metric space. The conformal predictor framework provides

confidence and credibility measures for the interpretation of results [ADA_6].

Automatic location of L/H transition time instants have been carried out for JET. The

difference of this work with previous ones resides in the estimation of a probability confidence

interval of the prediction [ADA_7]. Together with this analysis concerning the L/H transition, an

article related to the H/L transition in JET was published [ADA_8]. The estimated transition

times are qualified with measures (confidence and credibility) about how reliable the predictions

are.

The technique developed in JET [ADA_7] for the automatic recognition of L/H

transitions has been applied to the database of the DIII-D tokamak and the results were

published in [ADA_9].

http://labfus.ciemat.es/AR/2012/CAP2/ADA_1.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_2.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_3.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_4.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_3.pdfADA_4.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_5.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_6.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_7.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_8.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_7.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_9.pdf


Derivation of a scaling law for the H-mode power threshold using the ITPA Global H-

mode Confinement Database [ADA_10] was presented at the 7th Workshop on Fusion Data

Processing Validation and Analysis (March 2012).

Research not directly related to the confinement transition but related to the H-mode

has also been developed. In particular, results about the analysis of pedestal confinement

degradation, induced by ELMs in JET [ADA_11] were presented at the 7th Workshop on Fusion

Data Processing Validation and Analysis (March 2012). An important aspect of the investigation

is the automatic location of ELMs. This automatic method has allowed the analysis of 748 JET

discharges and 46187 ELMs [ADA_12].

2.2.6.3 IMAGE PROCESSING

Advanced image processing methods have been an important activity during 2012. Two

different compilations of present techniques were respectively presented at the 7th Workshop on

Fusion Data Processing Validation and Analysis (March 2012) [ADA_13] and published in

[ADA_14]. State of the art techniques were developed and applied according to the following

table:

Work Conference Article

Recognition of the most

important regions to develop image

classifiers

ADA_15

Development of active learning

techniques for image classification by

using conformal predictors

7th Workshop on

Fusion Data Processing

Validation and Analysis

(March 2012): ADA_16

ADA_17

Noise reduction in the TJ-II

Thomson Scattering images

7th Workshop on

Fusion Data Processing

Validation and Analysis

(March 2012): ADA_18

ADA_19

Image de-noising 10th International

FLINS Conference: ADA_20

Image classification using

phase congruency

ADA_21

Improved techniques for fast

image recognition in the conformal

27th SOFT

Symposium (September

http://labfus.ciemat.es/AR/2012/CAP2/ADA_10.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_11.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_12.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_13.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_14.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_15.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_16.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_17.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_18.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_19.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_20.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_21.pdf


2.2.6.4 OTHER WORKS

This subsection includes a miscellanea of works on advanced data analysis techniques

not related with anyone of the above subsections.

To start, it should be mentioned a publication of an overview about statistically hedged

prediction methods [ADA_23].

In the 7th Workshop on Fusion Data Processing Validation and Analysis (March 2012),

an invited talk about data-driven models was given [ADA_24]. In the same Conference, two

other contributions were presented. On the one hand, a work on model selection criteria

[ADA_25] was described. On the other hand, the integration of GPU technologies for real-time

data analysis was discussed [ADA_26].

A novelty research on conformal predictors based on fuzzy logic classifiers [ADA_27]

was presented at the International Conference “Artificial Intelligence Applications and

Innovations” (September 2012) and it also has been published [ADA_28]. Last but not least,

new classes of indicators for the selection of scaling laws in fusion were presented in

September 2012 at the 27th SOFT Symposium [ADA_29].

2.3 REAL TIME MEASUREMENT AND CONTROL

2.3.1. ADVANCED DATA ACQUISITION SYSTEMS

This section is devoted to explaining the work carried out on two ITER Fast Plant

System Controller prototypes during 2012. Two form factor prototypes were tested: PXIe and

ATCA. A general description about the prototype based on the PXIe form factor can be found in

[ADAQ_1]. The equivalent development on ATCA is [ADAQ_2]. CIEMAT has been most

involved in the PXIe form factor and several contributions to Conferences and articles detail

specific parts of the PXIe prototype. A first work to be mentioned is the oral presentation in the

7th Workshop on Fusion Data Processing Validation and Analysis (March 2012) on the data

acquisition and pre-processing implementation of FPGA-based cards [ADAQ_3]. Taking into

account the large processing capabilities of the data acquisition systems in ITER, the integration

of GPUs in the PXIe prototype was tested in [ADAQ_4]. Due to the fact of the high demanding

archiving requirements, a particular solution based on NetCDF was analysed in [ADAQ_5].

Finally, the integration of the FlexRIO technology and EPICS was discussed in a contribution

[ADAQ_6] to the 18th Real-Time Conference (June 2012).

2.3.2 REAL-TIME DISRUPTION PREDICTORS

The impact of disruptions in JET became even more important with the replacement of

the previous Carbon Fiber Composite (CFC) wall with a more fragile full metal ITER-like wall

(ILW). The development of robust disruption mitigation systems is crucial for JET (and also for

predictor framework 2012): ADA_22

http://labfus.ciemat.es/AR/2012/CAP2/ADA_23.pdfhttp://labfus.ciemat.es/AR/2012/CAP2/ADA_24.pdfhttp://labf

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