1 / 8

Status of the 2008 ASC TSG Run plan

Office of Science. Supported by. Status of the 2008 ASC TSG Run plan. College W&M Columbia U Comp-X General Atomics INEL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics New York U Old Dominion U ORNL PPPL PSI Princeton U SNL Think Tank, Inc. UC Davis UC Irvine UCLA

gracie
Download Presentation

Status of the 2008 ASC TSG Run plan

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Office of Science Supported by Status of the 2008 ASC TSG Run plan College W&M Columbia U Comp-X General Atomics INEL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics New York U Old Dominion U ORNL PPPL PSI Princeton U SNL Think Tank, Inc. UC Davis UC Irvine UCLA UCSD U Colorado U Maryland U Rochester U Washington U Wisconsin Culham Sci Ctr U St. Andrews York U Chubu U Fukui U Hiroshima U Hyogo U Kyoto U Kyushu U Kyushu Tokai U NIFS Niigata U U Tokyo JAEA Ioffe Inst RRC Kurchatov Inst TRINITI KBSI KAIST ENEA, Frascati CEA, Cadarache IPP, Jülich IPP, Garching ASCR, Czech Rep U Quebec Presented by D. A. Gates (J. Menard Deputy) At the NSTX Mid-run asessment PPPL April 16, 2008 1

  2. XP-823 “Robustness of improved error field suppression in long-pulse discharges” – Day 1 GOAL: Extend optimal EFC to wider range of scenarios and IP STATUS – 1 run day so far for XP-823 Determine optimal n=3 EFC gain relative to IPF5 and/or IP • Re-verify existence of n=3 EF in IP=900kA reference discharge • STATUS: re-verified at 700kA with early H-mode. • n=3 EF was less apparent w/o early H-mode • Optimize n=3 EFC for two new plasma currents: 700kA and 1.2MA • STATUS: Optimal EFC current at 700kA was similar to level at 900kA Is EFCC proportional to IP? • Need to optimize at 1.1-1.2MA to determine proportionality – needs 6-8 shots Test combined n=3 EFC + n=1 RFA suppression for IP=0.7, 0.9, 1.2MA • Add n=1 feedback – 2 shots for each IP – use optimal 2007 gain & phase • STATUS: Worked well at 900kA, worked ok at 700kA but plasma still disrupted suggesting higher gain might be beneficial • Need data at 1.1-1.2MA – need 3-4 shots Day 1 2

  3. XP-811 Vertical Stability Physics and Performance Limits in Tokamaks with Highly Elongated Plasmas • XP complete in 1/2 run day • Measured zmax , the maximum controllable vertical displacement, by turning of the plasma control and then tuning it back after the plasma had drifted vertically • Interim report written and distributed to the ITER team which was well received • “Dear David, Many thanks - the report makes very interesting reading and the work behind it is very valuable for us. Best Wishes, David Campbell” • Detailed analysis ongoing 3

  4. XP-823 “Robustness of improved error field suppression in long-pulse discharges” - Day 2 STATUS – Day 2 plan has not yet been run – scheduled for April 28 Completing XP-823 may require additional 1.5 days vs. 1 day asked for Optimize n=1 RFA suppression controller • Reproduce 2007 900kA reference shots which used externally applied n=1 error field to trigger rotation collapse and disruption (3 shots) • Scan RWM control proportional gain until feedback system is unstable (4 shots) • Add LPF to control coil currents as necessary to avoid very large SPA currents • With gain at highest stable value, increase tLPF from 0 to: • 1ms, 3ms, 10ms, 30ms, 100ms (2 shots for each LPF) (10 shots) • For tLPF where AC RMS control power is reduced by factor 2-4, increase gain again and determine highest stable value (4 shots) • Test controller for two new plasma currents: 700kA and 1.2MA (4 shots) Day 2 4

  5. XP-826 "X-point limiter plasmas" Goal: Investigate benefit of this configuration Status: Scheduled for review • Investigate plasma configurations where dominant lower X-point is brought very close to, or possibly outside, the outer divertor plate • Possible alternative way to reduce divertor heat flux • Assess access to H-mode, energy confinement and heat flux on divertor • The initial experiment is planned to be run before lithium coating • If successful, perform a second round with lithium on the lower divertor 5

  6. XP-8** - Impact of 2 LITER system on long-pulse discharges STATUS – XP has not been run – waiting for dual LITER – requests 1.5 days • Goal is to determine if usage of 2 LITER system can: • Eliminate He glow, or reduce glow time to  5 mins • Will likely be done in boundary physics TSG XPs • Lower the electron density, and achieve density flat-top • Likely requires SGI to replace HFS gas • Increase the NBICD fraction of long-pulse discharges • Significant shot development will be needed to optimize low ne operation • Obtain sufficient flat-top duration to “measure” NICD profiles w/ VLOOP analysis • Methodology • Reduce/eliminate HFS gas by utilizing SGI – 0.5 days • Find lower bound of HFS pressure, incrementally add SGI • If/when plasma disrupts in ramp or early flat-top, optimize early shot phase to obtain flat-top sufficient for NBI-CD analysis – 1 days (optimistic!) • Vary beam timing and power • Vary plasma current ramp-rate and flat-top value • Vary early density/SGI fueling rate 6

  7. XP-8** Parametric study of high elongation plasmas Goal: Investigate high elongation low-li scenario first developed in 2007 Status: Waiting for LITER • Use second LITER and experience gained to optimize wall conditions • Use n=1 feedback and n=3 correction to improve performance (higher ) • Previous attempts limited to N < 4 • Perform current and field scan to optimize non-inductive current fraction 7

  8. XP status summary 8

More Related