high priority mhd research coordination in preparation for the 2008 fwp d. a. gates, mhd sfg leader...
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High priority MHD research coordination in High priority MHD research coordination in preparation for the 2008 FWPpreparation for the 2008 FWP
D. A. Gates, MHD SFG Leader
MHD Science Focus Group MeetingB318 PPPL
December 12, 2008
College W&MColorado Sch MinesColumbia UComp-XGeneral AtomicsINELJohns Hopkins ULANLLLNLLodestarMITNova PhotonicsNew York UOld Dominion UORNLPPPLPSIPrinceton UPurdue USNLThink Tank, Inc.UC DavisUC IrvineUCLAUCSDU ColoradoU MarylandU RochesterU WashingtonU Wisconsin
Culham Sci CtrU St. Andrews
York UChubu UFukui U
Hiroshima UHyogo UKyoto U
Kyushu UKyushu Tokai U
NIFSNiigata UU Tokyo
JAEAHebrew UIoffe Inst
RRC Kurchatov InstTRINITI
KBSIKAIST
POSTECHASIPP
ENEA, FrascatiCEA, Cadarache
IPP, JülichIPP, Garching
ASCR, Czech RepU Quebec
NSTXNSTX Supported by
NSTXNSTX PPPL MHD Science Focus Group meeting 2Dec. 12, 2008
SFG meeting goals
• “to provide recommendations/input for strengthening PPPL's FWP's for the coming year”
• Promote discussion that stimulates exchange of ideas
• Exchange information amongst MHD researchers on the MHD related activities of the laboratory
• Disseminate important information regarding international burning (ITER/ITPA) plasma research priorities
NSTXNSTX PPPL MHD Science Focus Group meeting 3Dec. 12, 2008
Focus of 2009 work plan for ITER MHD TG
• ITER Urgent R&D Needs
• Disruptions (control, mitigation, loads) – major theme• Plasma control
– Vertical Stabilization– NTM stabilization– Sawtooth control – RWM control– Error Field control
• Implementation
• Joint experiments (MDC 1,2,4,5,8,12-14,15-17)• Theory/Modeling
Scenario Development}
NSTXNSTX PPPL MHD Science Focus Group meeting 4Dec. 12, 2008
Joint Experiments
Continuing
MDC-1 Disruption mitigation by massive gas jets
MDC-2 Joint experiments on resistive wall mode physics
MDC-3 NTM physics (incl. error field effects) Closed (2008)
MDC-4 NTM physics - aspect ratio comparison
MDC-5 Sawtooth control methods for NTM suppression
MDC-8 Current drive prevention/stabilisation of NTMs
MDC-12 Non-resonant magnetic braking
MDC-13 Vertical stability physics and performance limits
MDC-14 Rotation effects on NTMs (+ remainder of MDC-3)
New (proposed)
MDC-15 Disruption database development
MDC-16 Runaway electron generation, confinement, and loss
MDC-17 Physics-based disruption avoidance
[MDC-10 and MDC-11 transferred to Energetic Particles group]
NSTXNSTX PPPL MHD Science Focus Group meeting 5Dec. 12, 2008
Disruptions
• Electromagnetic loads – vertical & horizontal – due to halo currents, disruptions and VDEs
– Improve 2D (DINA, TSC) and 3D halo current models– Extend ITPA disruption database: focus on halo currents
• Runaway electrons
– Diagnostics for generation, confinement, loss
– Physics basis for runaway suppression by gas injection, MHD activity, or RMP
• Requirements for ITER’s disruption mitigation system
– Experiments and modeling (NIMROD, SOLPS, …)
– Gas injection
– Alternate delivery methods such as pellet injection
• Disruption prevention
– ECRH heating of precursor islands
– Feedback stabilization of NTMs, RWMs or forced rotation of
precursors
NSTXNSTX PPPL MHD Science Focus Group meeting 6Dec. 12, 2008
Plasma Control Issues - Vertical Stability
• Safe operation limit: ZMAX /a > 5%
• Confirm design of in-vessel coils – Characterize plasma disturbances, e.g. ELMs
– Effects of noise, disturbances on ITER controllability limits
– Up-gradation of VS1 & VS2 as a backup?
– Scaling with parameters other than li , …
• Joint Expt (MDC-13): DIII-D, C-Mod, JET, NSTX– Refine past exptal findings on controllable vertical
displacements and compare with model predictions
– D Humphreys (DIII-D), I Hutchinson (C-MOD), F Sartori (JET), D Gates (NSTX), W Treutterer (AUG), J Lister (TCV)
NSTXNSTX PPPL MHD Science Focus Group meeting 7Dec. 12, 2008
Plasma Control Issues - NTM Stabilization
• Requirements for ECCD detection and stabilization– Determine diagnostic requirements for island detection– Confirm power requirements– Launcher capability for planned operating scenarios
• Rotation effects– On threshold N – strong evidence from DIII-D, JET, NSTX– Rotation vs rotation shear, direction of rotation– Theoretical understanding lacking
• Scaling of NTM limiting with other parameters
• Suppression through sawtooth control
NSTXNSTX PPPL MHD Science Focus Group meeting 8Dec. 12, 2008
RWM Control
• Requirements for control coils and their power supplies– Current, voltage, frequency, toroidal mode requirements for RWM stabilization using
• ELM control coils• External EFC coils
– Effects of noise and plasma disturbances on the control system
• Relook at RWM stability thresholds and destabilization mechanisms (critical velocity concept may not be adequate)
– cross-machine comparison of RWM onsets and related MHD activities that may act as triggers
• ELMS or fishbones, • EWM • RWM to kink
– Identify possible nonlinear destabilzation mechanism
• Continue benchmarking of RWM feedback codes
• RFA expts and validation of theoretical models
NSTXNSTX PPPL MHD Science Focus Group meeting 9Dec. 12, 2008
Error Field Control
• Error Field Correction: design of EFC methods– Criteria for EF tolerance in all operating scenarios– EFC methods for ITER: vacuum meas., plasma response
• Effects of ferromagnetic steel in Test Blanket Modules: design of correction coils– Potential effects of TBM fields on many aspects of operation,
including equilibrium reconstruction– Modeling needed to quantify these effects– Simulate TBM fields in existing devices?
• Non-resonant Magnetic Braking– n=1,2,3 external magnetic perturbations– Validation of neoclassical toroidal viscosity models
NSTXNSTX PPPL MHD Science Focus Group meeting 10Dec. 12, 2008
Schedule for MHD SFG meeting
• 1:30 - 1:45 Introduction and ITPA/ITER high priority topics in MHD - Dave Gates (15minutes)
• 1:45-1:55 Space Physics MHD research at PPPL - Jay Johnson (10 minutes)
• 1:55 - 2:10 Non-Stellarator MHD Theory - Steve Jardin (15 minutes)
• 2:10-2:20 MRX related MHD research - Masaaki Yamada (10 minutes)
• 2:20-2:30 MRI experiment - Mark Nornberg (10 minutes)
NSTX MHD research– 2:30-2:40 RWM and NTV related research - Steve Sabbagh (10 minutes)– 2:40-2:50 Disruptions, NTMs, Error fields, and IPEC - Stefan Gerhardt (10 minutes)– 2:50-3:00 Scrape off layer currents on NSTX - Hiro Takahashi (10 minutes)
• 3:00-3:15 Stellarator related MHD research - Hutch Nielson (15minutes)
• 3:15-close General discussion about contents of presentation to the research council
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