ccfe is the fusion research arm of the united kingdom atomic energy authority presentation on...

CCFE is the fusion research arm of the United Kingdom Atomic Energy Authority

Presentation on prioritisation of DIVSOL

proposals for M9

Andrew Kirk

Andrew Kirk MAST team meeting 28/11/12

M9 Top Level Goals

• Understanding ELM control by RMPs• Understanding pedestal stability using measured

edge current and flows• Test the ion-scale transport paradigm quantitatively• Develop a MAST-U relevant scenario (low-li H-

mode, no P3 coil) matched by a semi-empirical simulation

• Generate a mean-value and fluctuation SOL ne database to develop modelling tools for super-X

• Understanding fast-ion transport from visible modes to guide q(r) and beam source config


M9 proposals received

20 proposals received requesting 240 shots

Following an internal review and PLF

2 proposals have been merged with others

10 priority 1 proposals remain with 114 shots allocated

There are 4 priority 2 proposals that 40 potential extra shotswould get time if the accompanyingpriority 1 proposal is successful


M9 proposals linked to top Level Goals

Number NameSOL-001 Characterization of the SOL physics in L-mode 24SOL-002 Direct Measurements of Plasma Potential Fluctuations 16SOL-003 SOL fall off length measurements during inter-ELM periods 10SOL-004 Divertor ion temperature measurements 20SOL-004b RFEA Ion and Electron Temperature Measurements in L-mode plasmas. 0SOL-001,2b Heavily diagnosed plasma study 0

Total 70


SOL-008 Benchmarking of new Coherence Imaging flow diagnostic 7SOL-009 Flow imaging of multiple impurity species in the divertor 7SOL-010 NIR spectral survey 0

Total 14

M9 proposals linked to MAST_U


Other P1 M9 proposals

Linked to Phds/ basic science

SOL-005 Divertor Impurity transport studies 10SOL-006 Identification of Geodesic Acoustic mode in MAST L-mode plasma 8SOL-007 Fast Imaging of Heat Pulse Propagation in the Divertor 12

Total 30


M9 proposals – that could become P1

SOL-013 Impact of plasma parameters on GAMs 16SOL-014 GAM effect on the LH transition 20SOL-018 Divertor flow imaging under changing SOL / Div conditions 10SOL-019 Wide coverage imaging of He II flows in Helium plasmas 13SOL-017 NIR spectroscopy in recombining detached divertor plasmas 4

Total 63

Shots that would fight for the contingency if previous shots are successful


SOL-001 Characterisation of SOL physics in L-mode

Shots:24

• Determining and understanding how the SOL responds to plasma and geometrical changes is crucial in order to predict its behaviour in long divertor configurations (MAST-U) or in the next generation tokamaks (ITER, DEMO).

• Recent theoretical models (Miltello PPCF 2012) provide a scaling of the SOL width as a function of the edge parameters, finding a direct dependence with respect to the density and inverse with respect to the plasma current and electron temperature. Experimental (Scarabosio et al. PSI 2012)

Theoretical (Militello et al. PPCF, submitted Aug 2012)

• Similar trends are found in experimental results from conventional tokamaks although the scalings are based on engineering parameters

Aim: Characterise the L-mode upstream SOL decay length in terms of local edge parameters


# Ip BT NBI

1-4 400kA 0.4T /

5-8 400kA 0.585T /

9-12 600kA 0.585T /

13-16 600kA 0.585T 1 source

SOL-001 Characterisation of SOL physics in L-mode

Changes q and B

Changes T and B or q

Changes T

Parameters to scan: density, temperature, magnetic field, q95, length of SOL

Diagnose the edge plasma as completely as possible


SOL-002 Measurement of plasma potential fluctuations

Measurements will be made with the adapted Gundestrup probe

Plans to measure

• RMS potential profiles to investigate decay length and structure and compare with density, temperature

• Potential near the seperatrix to investigate difference between closed and open field line regions

• Fluctuation PDF of potential and density from which we can compare PDF moments against theory

Shots:16


[Eich et al, IAEA 2012]

NSTX

• Present assumption for ITER is q ~ 3 mm

• Measurements from a range of tokamaks suggest that the fall off length is much

smaller than this: qITER ~ 1 mm [Eich et al, PRL 107 (2011) 215001]

• Heat flux profiles are fitted using a fall off and diffusion term;

– Convolution of a gaussian and an exponential profile

• MAST IR profiles are well fitted by this profile and fit the trend of other machines

SOL-003 SOL fall off length measurements inter-ELM

Shots:10


SOL001-3b Heavily Diagnosed Plasma Study

Create low and high density reference shots

– Ip = 600kA, 1 beam, L-mode double null

– Magnetic feedback for RP measurements, optimise for divertor RFEA

– Repeat to take data using IR, LPs, DivCam (Dα, Carbon, Helium lines), coherence imaging, different BES positions

– Repeat when different RP heads become available

Specific Diagnostics: RP, DivCam, IR coverage of both divertors, BES position scan, coherence imaging, DSF RFEA

Proposal combined with SOl001,2,3


• Obtain complete target profiles during inter-ELM and ELMs combined with midplane measurements

• Obtain target and mid-plane ion temperature measurements in L-mode

SOL-004 Ion temperature measurementsShots:20


SOL-005 Divertor impurity studies

CII filtered light Initial experiments in low power shots

Goal to inject into H-mode shots with significant parallel Temperature gradient

Obtain flow data and C transport for comparison with modelling

Shots:10


SOL-006 Identification of GAMs

Aim: To verify that GAM-like oscillations are observed in the baseline scenario 1 discharge (21856) with Ip=400 kA, B0=0.52 T and q95=6 using active and passive diagnostics: reciprocating probe, EBW, Thomson scattering

If successful would go on to determine its dependence on plasma parameters

Numerical modeling with CENTORI code suggests a strong dependence of GAM properties on plasma parameters such as q95, ratio of ion and electron temperatures and plasma elongation.

Shots:8


SOL-007 Fast heat pulse propagation in the divertor

A time-dependent model for the influx of W from the ITER divertor during ELMs is being developed at the IO using the OSM-EIRENE-DIVIMP code package. Benchmarking is required of course, and MAST provides an opportunity for direct imaging of the heat pulse propagation via filtered high-speed camera imaging, specifically CII, CIII and He, which have well defined “temperature emission bands”.

Shots:12


SOL-008 Benchmarking of coherence imaging

• Coherence Imaging (CI) is a powerful technique for 2D ion flow (and possibly Ti) imaging using Doppler spectroscopy of visible emission, and enables tomographic inversion to recover flows on an R-Z cross-section. It is already being used for passive flow measurements on DIII-D.

• A new CI diagnostic has been developed for MAST in a collaboration between Durham University, CCFE, Australian National University and York University, and will be installed for the first time for M9.

• Before experiments using this diagnostic, it is important to benchmark the instrument against an existing flow measurement to ensure we fully understand the output of this new system.

• This proposal is to benchmark CI against ECELESTE by simultaneously measuring outboard midplane He II flows with both diagnostics.

Shots:7


SOL-009 Flow imaging in the divertor

The new Coherence Imaging diagnostic with its wide-angle divertor view gives us the opportunity to image divertor flows of multiple species over the entire divertor cross-section.

By measuring multiple species in repeated shots we can look at the behaviour of different charge/mass impurity flows and possibly extend the spatial coverage (due to different spatial distributions of the different ionisation states)

Shots:7


SOL-010 NIR spectral survey

Aim: To investigate the diagnostic potential of NIR (800-2500nm) spectroscopy by collecting survey spectra for a variety of plasma conditions and to compare UV-VIS line and continuum emission to NIR spectra.

Shots:0


Summary

Most of the proposals (SOL-001-SOL—4) help us to meet the top level goal of

Generate a mean-value and fluctuation SOL ne database to develop modelling tools for super-X

As well as investigating diagnostics for MAST_U (SOL-008-010)

The remainder look at completing basic science studies (SOL-005-SOL-006) and one is directly related to ITER (SOL-007)

ccfe is the fusion research arm of the united kingdom atomic energy authority presentation on...

Documents

andrew kirk mast team

m9 andrew kirk slide

u slide

successful slide

length of sol

p1 m9 proposals

possible slide

sol width