high priority mhd research coordination in preparation for the 2008 fwp d. a. gates, mhd sfg leader...

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


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}


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]


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


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)


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


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


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


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

high priority mhd research coordination in preparation for the 2008 fwp d. a. gates, mhd sfg leader...

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