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Supported by. Columbia U Comp-X General Atomics INEL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics NYU ORNL PPPL PSI SNL UC Davis UC Irvine UCLA UCSD U Maryland U New Mexico U Rochester U Washington U Wisconsin Culham Sci Ctr Hiroshima U HIST Kyushu Tokai U
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Supported by Columbia U Comp-X General Atomics INEL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics NYU ORNL PPPL PSI SNL UC Davis UC Irvine UCLA UCSD U Maryland U New Mexico U Rochester U Washington U Wisconsin Culham Sci Ctr Hiroshima U HIST Kyushu Tokai U Niigata U Tsukuba U U Tokyo Ioffe Inst TRINITI KBSI KAIST ENEA, Frascati CEA, Cadarache IPP, Jülich IPP, Garching U Quebec Integrated Scenario Modeling of NSTX Advanced Plasma Configurations C. Kessel and E. Synakowski Princeton Plasma Physics Laboratory For the NSTX National Team APS Division of Plasma Physics Meeting October 27-31, 2003
Integrated Scenario Modeling is Focused on NSTX Advanced ST Milestones High and N Operating Targets for flattop > EST Physics at High Non-inductively Sustained for flattop > JCurrent Drive Techniques NBI + HHFW, HHFW only, and HHFW+EBW Non-solenoidal Current RampupBasis for Future ST Devices Non-inductively Sustained, High for flattop >> J Integrated Advanced ST Plasmas Ip = 1.0 MA, BT = 0.36 T, N = 8.85, = 41%, PNBI = 4 MW, PHHFW = 3 MW, PEBW = 3 MW
Shot 109070 Provides Basis for Integrated Scenario Modeling in TSC Shot 109070 was chosen as a good prototype for longer pulse NBI scenarios tflat > J for Ip and INI / IP > 50% N = 5.9, H98 = 1.2 TSC benchmark simulation of 109070 TRANSP, S. Kaye
Strong Suppression of HHFW CD from NB Fast Ions and for Ti/Te >1 Beam ions absorb 50-98% of HHFW power ---->seen in beam ion energy on experiment Thermal ions absorb 0-40% of HHFW power ----> no experimental verification so far Most of the HHFW power is absorbed before waves reach axis, low k|| suffers most However, HHFW current drive without NBI reaches up to 140 kA/MW No CD is assumed from HHFW in scenarios that include NBI
NSTX Can Operate for Several Current Relaxation Times Depending on the TF Field Accessible TF Coil flattop time 6.0 J = 670 ms Non-inductively Sustained, High 5.0 4.0 J = 500 ms Non-inductively Sustained 3.0 Time, sec J = 230 ms (109070) 4 J 2.0 2 J 1.0 0.0 3 3.5 4 4.5 5 5.5 6 Bt (kG)
PF1 Coil Modification Leads to Simultaneous High Elongation and High Triangularity Present shaping capability PF1 Modification =2.6,=0.8+ =1.9,=0.8 =2.6,=0.4
EBW CD Provides Off-Axis Current Profile Control G. Taylor, PPPL B. Harvey, CompX
Time-Dependent Simulations of Non-inductively Sustained, High Plasmas in TSC • Lower BT to access high and N values and long pulse lengths • Inject • 4 MW NB heating and CD on axis • 3 MW HHFW heating (no CD) • 3 MW EBW heating and CD off-axis • Utilize simultaneous high elongation and high triangularity from PF1 modification • Assume density control and slight density peaking near plasma edge from lithium pellets or pumping, n(0)/<n> = 1.1
Non-Inductively Sustained, High PlasmaIntegration Target is Reached • Ip = 1.0 MA, Bt = 0.36 T • IBS = 430 kA, INB = 430 kA • IEBW = 100 kA • = 2.55, = 0.83 qcyl = 2.5, li(1) = 0.4 = 41.3% N = 8.85 E = 37 ms H98 = 1.5 n(0) n poloidal flux ion electron
Pressure Profile and Current Profile Lead to Stable High Plasma with fNI ≈ 1, Sustained for 4J EBW off-axis current critical for ballooning stability Reach = 41%, N = 8.85, for 4 J with Ip = 1 MA, BT = 0.36 T Stable to high-n ballooning* and n=1 kink modes with outboard wall at 1.5a PF1 coil modification critical to accessing high N by providing high and high together V/ Vo * except in pedestal region
Further Investigations and Development for Integrated Scenario Modeling • HHFW CD efficiency • Fast ion absorption • Thermal ion absorption • Full wave (AORSA) and ray-tracing benchmarks • EBW CD • Continue modeling and parameter dependences • Plasma transport • Continue to rely on expt. ’s as discharges move closer to scenarios • Use NSTX specific global scaling • Pursue a Low A predictive transport model • NBI analysis • Apply TRANSP beam analysis to TSC high cases • MHD stability • Vertical stability/control of high plasmas • Identify more accurate -limits ---> conductors geometry, plasma rotation, higher n RWMs, RWM feedback, FLR & flow stabilization for high-n
NSTX is Using Integrated Scenario Modeling to Plan Future Experiments • Advanced ST plasmas have been identified • Non-inductively Sustained for flattop > J, • Non-solenoidal current rampup, • High and N Operating Targets, • Non-inductively Sustained, High for flattop ≈ 4 J, • Ip = 1.0 MA, BT = 0.36 T, N = 8.85, = 41%, PNBI = 4 MW, PHHFW = 3 MW, PEBW = 3 MW • Critical tools to accessAdvanced ST plasmas • HHFW heating with NBI, and heating/CD without NBI on/near-axis • EBW CD off-axis • Strongplasma shaping through PF coil modification • Density control thru pumping or lithium