Upload
symona
View
29
Download
0
Embed Size (px)
DESCRIPTION
TORE SUPRA. IOS-5.2 Maintaining ICRH Coupling in expected ITER regime Spokes person: M. Goniche M.-L. Mayoral (JET), R. Pinsker (DIII-D), L. Colas (TS), V. Bobkov (AUG), S. Wukitch (C-Mod), J. Hosea (NSTX), J.G. Kwak (KSTAR), S. Moriyama (JT60-U) - PowerPoint PPT Presentation
Citation preview
IOS-5.2Maintaining ICRH Coupling in expected ITER regime
Spokes person: M. GonicheM.-L. Mayoral (JET), R. Pinsker (DIII-D), L. Colas (TS), V.
Bobkov (AUG), S. Wukitch (C-Mod), J. Hosea (NSTX), J.G. Kwak (KSTAR), S. Moriyama (JT60-U)
7th Integrated Operation Scenarios Topical Group MeetingKyoto, Japan, 18–21 October 2011
TORE SUPRA
Status
• The JE has not progressed much since the Culham meeting
• DIII-D : New experimental results
• JET : 1st ICRF pulse on plasma on Oct.6
• AUG: No new results, planned experiment in 2011, delayed to 2012
• Tore Supra: No new results due mainly to the poor availability of the ICRH system during 2011 campaign, delayed to end of 2012
• C-Mod: No new results, ?
• NSTX: Status of edge density effect on edge RF power deposition presented at EPS11 in Strasbourg
• KSTAR : ?
TORE SUPRA
Aims for 2011 as planned in April 2011 / present status • Have better understanding of local modification of electron density profile near
the antenna when gas is puffed
– new gas injection systems (DIII-D, Tore Supra, KSTAR)
Installed on DIIID and Tore Supra, KSTAR ?
– combined with new or upgraded reflectometer (DIII-D, C-Mod, Tore Supra)
Installed and tested (C-Mod) , installed and tested, data to be analyzed (DII-D)
• Exploring the role of near fields for enhancing the ionization rate and therefore the electron density.
– new experiments on AUG
Delayed to 2012
• Investigate control in real-time reach wanted level of coupling while minimising gas injection
– envisaged in JET
Still foreseen as back-up experiment
• Investigate the upper limit of edge density
– NSTX
Mine data to substantiate location of edge deposition in SOL – develop new edge diagnostics for NSTX-U
TORE SUPRA
Local and polidally distributed gas injection improves antenna loading significantly (~×2) [Ph. Jacquet, V. Bobkov et al., to be submit.to NF] No density measurements close to the antenna (or gas valve)
ICR moved to Ant.3 in 2011 with Li-beam close to it
Increase of AUG ICRF antenna loading by local gas injection
(Gas)(Gas)
(Gas)
A1
ICR-4
Experiments on gas puffing to enhance Fast Wave antenna loading in DIII-D (August 2011)
• Compare loading at low (0.2kW) and medium power (70kW) – 0deg and 280/300
antenna– 307 and 10 deg Gas
Puff
• Data available from one at 307 deg (ORNL), and 240 deg (UCLA) reflectometer (not yet analyzed)
DIII-D Top view
RF10 Gas puff
307 Reflectometer
240 Reflectometer
~0.2 kW
~70 kW
285/300~1/RL
0 deg~1/RL
Outer gap (m)
D-alpha
RF307 puff
August 2011: puffing at 307 deg enhances loading at 285/300, at 0.2 kW or 70 kW, with almost no effect
on 0 deg loading
~0.2 kW
285/300~1/RL
0 deg~1/RL
Outer gap (m)
D-alpha
RF10 puff
Puffing at 10 deg enhances loading at both 0 deg and at 285/300 – only global effect
• Effect on 0 deg and on 285/300 loading are similar, and are tracked by D-alpha signal (onlyweak prompt response to puff)
• If any difference, effect on 285/300 is slightly stronger than on 0 deg
~0.2 kW
C-Mod IOS 5.2 Status: SOL Reflectometer is Operational
en
Poloidally distributed gas injection near E antenna- Reflectometry measurements not too far from E antenna
Gas puff
Poloidally distributed valve & reflectometer not too far from Q5Polidally distributed valve in Q5 side limiter under discussion
Reflectometer& Probes
Poloidally distributedvalve
Reflectometer embedded in LHCD antenna (no horns)
Confined plasma
SOL
• Rather high S/B => detection of the plasma/vacuum interface difficult
• Data processing improvement on-going
• S/B improved by a factor 10 for the 2012 campaign
ICRH antLCFSfiltered
unfiltered
Bottereau/Pham
Issue 1: Local vs Global effect in SOL
JET: Not very clear (slight local effect with GIM6 puff?)
AUG : Local effect for A1 (single injection point) & ICR-A (poloidally spread) (×2)
Tore Supra : no local effect at rather low gas rate
test higher gas rate and LHCD-assisted gas ionization
DIII-D: Local effect with RF307 puff (×2)
~Global effect with 10deg puff
test poloidally spread gas puff RFCOMB
C-Mod: to be tested
TORE SUPRA
Issue 2: ICRF Power level effect
JET: not adressed
AUG : to be tested in next campaign
Tore Supra : not adressed
DIII-D: same Local effect with RF307 at 0.2kW & 70k to be confirmed at ~1MW in next cmpaign
C-Mod: to be tested
Issue 3: Gas rate level effect on confinement / ELMs
JET: Decrease of H98 by ~15% for F~1022el./s
AUG :
Tore Supra : Limiter, no H-mode, Fmax~1021el./s
DIII-D: Decrease of H98 by ~20% for F~1022el./s
C-Mod:
TORE SUPRA
Poloidally spread injection near antenna
Reflectometer
Li beam Reciprocating probe
Status
JET Yes, 20° Yes, far away
Yes, far but magn. connected
Yes, far but magn. connected
Tested but scarce ne
profiles
AUG Yes, 0° Yes, far away
Yes, far away, close in 2011
Tested
Tore Supra Yes, 40° Yes, 40°
No Yes, far but magn. connected
Tested but no reflec. prof.
DIII-D Yes , 0° Yes, 25°
No No Not tested
C-Mod Yes, 40° Yes, 40°
Not tested
NSTX Yes (part of the antenna)
Yes, 0°
KSTAR Planned Yes, far away
Yes
TORE SUPRA
ICRH with poloidally spread gas injection : status
Enhancement / modifications of ICRH systems for 2012-2013
JET: Metallic wall (from Oct.2011)AUG in 2012, two antennas with B-coated side limiters to make operation easier. After 2012, two new 3-strap antennas for better compatibility with W wall
Tore Supra : Restart in Sept.2012 , back to 3 identical Faraday shields
DIII-D:
C-Mod:
NSTX: Improve voltage standoff on test stand for additional power capability on NSTX Upgrade at higher B field
KSTAR:
TORE SUPRA
Conclusions
• Installation/test of new gas injection systems and density measurments (reflectometers) is almost completed
• New findings on DIII-D (no IC power effect, local/global effect) need to be confirmed & more documented (use of RFCOMB on DIII-D, new experiments on AUG & other machines)
• Question on how close the gas injection system has to be should be answered (comparing results from AUG, DIII-D, C-Mod, JET)
• Modelling effort (expansion of neutral gas and ionization in SOL from nozzle or poloidally spread injection) needed
• We expect more results in 2012!