1j. stober, ec17, deurne, may 2012 ecrh on asdex upgrade system status, feed-back control, plasma...

J. Stober, EC17, Deurne, May 2012 1

ECRH on ASDEX Upgrade

System Status, Feed-Back Control, Plasma Physics Results

Max-Planck-Institutfür Plasmaphysik

J. Stober, A. Bock, M. Reich, F. Sommer, W. Treutterer, D. Wagner, L. Gianone,A. Herrmann, F. Leuterer, F. Monaco, M. Marascheck, A. Mlynek, S. Müller, M. Münich,

E. Poli, M. Schubert, H. Schütz, H. Zohm and the ASDEX Upgrade TeamMax-Planck-Institut für Plasmaphysik, EURATOM Association, Garching, Germany

A. Meier, Th. Scherer, D. Strauß, A. Vaccaro, J. Flamm, M. Thumm Karlsruhe Institue of Technology, EURATOM Association, Karlsruhe, Germany

H. Höhnle, W. Kasparek, U. StrothInstitut für Plasmaforschung, Universität Stuttgart, Stuttgart, Germany

A. Litvak, G.G. Denisov, A.V. ChirkovInstitute of Applied Physics, RAS, Nizhny Novgorod, Russia

E.M. Tai, L.G. Popov, V.O. Nichiporenko, V.E. Myasnikov, E.A. Soluyanova, S.A. MalyginGYCOM Ltd, Nizhny Novgorod, Russia


Status: 4 MW in plasma (almost) reached

plasma currentplasma density

ECRH Power140 GHz

ECE diode

Sniffer probes

Power in plasma

New system:2.4 MW @ 140 GHz (0.82 + 0.76 + 0.85)or2.1 MW @ 105 GHz (0.76 + 0.56 + 0.75)

Old system: 1.5 MW for 2 s @ 140 GHz


Status of the new System

3 x 2-frequency gyrotrons (10 s)

Output power 2.7 MW @ 140 GHz (0.91 + 0.82 + 0.95)2.3 MW @ 105 GHz (0.84 + 0.62 + 0.84)

Last gyrotron expected July 2012 (initially 2-f)

X2, X3 with all beamlines and frequenciesO2 reflectors only for beamlines 5 and 6 @ 140 GHzO1 only @105GHz for Bt > 3T


Multi frequency project – window issues

Gyrotron window

- grooved-disk concept too fragile (A. Vaccaro, KIT)

- final concept: separately mountable ring resonator

Torus window- double disk window (FZK/KIT)

successful low power tests in 2007but failure at high power 2011 (600 kW, 4s)

- ring resonator difficult on AUG due to space limitations

If the resonator-window works, we consider the project a success.Further development of DD-window is considered a new project.


Ring Resonator Window (G. Denisov, IAP)

Start w/o resonator mid 2012

Commission resonator early 2013

MOU


System Status:Topics addressed by other contributions

FADIS and in-line ECEtalks by W. Kasparek, W. Bongers, N. Doelman

ECRH Stray-radiationposter by M. Schubert


Feed-Back Control

ECRH/CD as actuator of discharge control system (DCS) :

Power control under DCS: on/off tested; analogue prepared

Mirror control under DCS: new system only, one axis only


New scheme: allows simultaneous central heating

old scheme:central ECRH impossible

new scheme:needs well focussed beam

NTM stabilisation - Concept


NTM control – FB control scheme

Real-Time Data Network

→ Torbeam

Gyro-trons

ECE

→

ECH,EQU

NTM,ECE NTM

Psetset

set

Te,ch

dB/dt

ECH

3/2 & 2/1corre-lation

z+()

z-

()

r

fch

MAX

B, m

rt-EQU

ne

DCNMirror drives

modelocation

ECE(ch,z)

pol(r, z)

q_res,EQU

ECH P

ne-profile

ne()

Data Acquisition Hardware

MSX

MHDcontroller

MIR

n=1 n=2analogue

from MIRd/d


NTM control – Launcher alignment

CorrelationECE&linear comb. ofMirnov datacorresponding to(n=2) or (2,1)

Amplitude

Phase

mode location

RT-TORBEAM

(M. Reich et al., FST 2012)


NTM control – First feed-back attempts (28.4.2012)

After ~ 100 ms minimum in n=2 amplitude

lose robust localization / tracking

rho (NTM) = rho (n=2) - 0.025

Wmhd

beta_pol

beta_N

ICRH

Amplituden=1n=2


Holographic Mirror with fast thermocouples to control beam position

1st pass

2nd passtop view

O2 heating – Concept (PhD-Thesis H. Höhnle)


O2 heating – FB control scheme

(FF) (FB)

on – off (FF)interlock Tmax


Example : O2 heating with FB control

TC for beam controland interlock

PO2 [MW]

ne [1020 m-3]

H-1

H-5

controllerthreshold

(TTC,b-TTC,t) Kp [a.u.]

Beam position after feedbackcontrol

Beam position before feedback control

TC forinterlock

poloidal launcher angle [mm]

mirror

FB – control correctslaunching angle within 50 ms


Plasma physics results

ECRH/ECCD is used in the majority of the AUG physics studies

review out of scope

Recent studies using high EC power

- L/H threshold at low density

P. Sauter et al., NF 2012

- Rotation and toroidal momentum transport

R. McDermott et al., PPCF 2011

- Advanced Tokamak scenarios

MSE analysis in progress

- Influence of heating mix on transport in H-mode (core/edge)


Comparison NBI - ECRH [- ICRH] (F. Sommer et al.)

H-mode, q95 = 4.0, fGW = 0.75

Wmhd ~ 350 kJ, Prad ~ 1.5 MW, fELM ~ 50 Hz, H98 ~ 0.8, βN ~ 0.95, eff ~ 2

Ptotal 3 MW

4 phases:- 0 NBI

2.7 ECRH- 0.8 NBI

2.0 ECRH- 1.6 NBI

1.2 ECRH- 2.4 NBI

0.6 ECRH


Influence of PECRH on kinetic profiles (ne, Te,i, vtor)

With increase of ECRH frac.

• ne

peaking increases

• Te

less than 600 kW ECRH 20% Te increase

• Ti

1/3 of ECRH power 15% decrease,effect saturates

• vrot_tor

decreases (reduced torque input)

only minor variations at the pedestal

NBI fraction rises


Ion heat transport increases with ECRH fraction

Increase of ion heat diffusivities as PECRH increases

- consistent with theoretical expectations for variation of Te/Ti

ECRH NBI2.7 MW2.0 MW 0.8 MW1.2 MW 1.6 MW0.6 MW 2.4 MW

3.0 MW

#27242

F. Sommer et al., accepted by NF


Outlook

ECRH-System

- New ECRH system will be completed in 2012 (2f)

- Long pulse 4f-gyrotron operation foreseen for early 2013

- Replacement of old system by 4 x 1MW/10s/2f in progress

Feed-Back Control

- Focus of FB control development in 2012 campaign on NTMs

- Flexible RT-diagnostic layer easily adapted to new tasks

Plasma Physics Studies

- Characterize dominantly EC heated H-modes at lower nu*

- many others


Future of multi-frequency project

a) close project- realisation of long-pulse mf-gyrotron would be big success.- In principle also suitable for torus, but not in AUG set-up.

b) continue- find reason for failure of DD-window (full wave simulation)- modify DD-Window if necessary.- build torus-window test-stand in Garching- start with high power short pulse, measure stray radiation and cooling requirements compare to calculation- long pulse tests in test-stand- mount DD-window to torus

under discussion with KIT


Zoom on edge profiles (ne, Te, vtor)

With increase of ECRH frac.

• ne

no change

• Te

10 % reduction

• Ti

no change

• vrot_tor_edge

decrease (reduced torque input)

• vrot_pol_edge

no change


Grooved disk too fragile (A. Vaccaro, KIT)

Details: A. Vaccaro et al. , Proceedings IRMMW 2011


Failure of double disk window

Conditioning with increasing pulse length

3 s pulse with 620 kW successfull (#26271)

4.1 s pulse with 580 kW lead to failure (#26277)

- Gyrotron switched of by inter-disk vac. control (5x10 - 4 mbar)- no arcs detected- water found in inter-disk volume

- Effect of non-perfect beam ?- Operation with 2 inclination?

Increase of stray radiation measured +7 db (post mortem).

Steam-bubble in cooling channel?


Broken double disc window

Air-side disk, light from behind


- minimum bandwidth 200 MHz must include frequency drift- accuracy of positioning < 5 m - needs evacuation 80 mm

KIT double disc window


torus-window test facility

3 Mitre bends+ wave guides

movable mirrorin load-MOU

wave guideconnectorto load-MOU

windowtestfacility


torus-window test facility


Comparison NBI - ECRH [- ICRH] (F. Sommer et al.)

• 27247 : LSN, H-mode, Ip ~ 1 Ma, Bt ~ 2.5 T q95 = 4.0, ne ~ 9 x 1019 m-3

• Constant global Plasmaparameter:

• Wmhd ~ 350 kJ, Prad ~ 1.5 MW, fELM ~ 50 Hz, H98 ~ 0.8, βN ~ 0.95, eff ~ 2

Ptotal 3 MW

4 phases:- 0 NBI

2.7 ECRH- 0.8 NBI

2.0 ECRH- 1.6 NBI

1.2 ECRH- 2.4 NBI

0.6 ECRH

1j. stober, ec17, deurne, may 2012 ecrh on asdex upgrade system status, feed-back control, plasma...

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