NSTX Project Facility and Diagnostic Plan, 5-Year Plan Preparation and NSTX/NCSX Relationship
Macroscopic Plasma Physics (MHD) Research 5 Year Plan: NSTX
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Transcript of Macroscopic Plasma Physics (MHD) Research 5 Year Plan: NSTX
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 1
Macroscopic Plasma Physics (MHD) Research5 Year Plan: NSTX
Supported byOffice ofScience
Culham Sci CtrU St. Andrews
York UChubu UFukui U
Hiroshima UHyogo UKyoto U
Kyushu UKyushu Tokai U
NIFSNiigata UU Tokyo
JAERIHebrew UIoffe Inst
RRC Kurchatov InstTRINITI
KBSIKAIST
ENEA, FrascatiCEA, Cadarache
IPP, JülichIPP, Garching
ASCR, Czech RepU Quebec
College W&MColorado Sch MinesColumbia UComp-XGeneral AtomicsINELJohns Hopkins ULANLLLNLLodestarMITNova PhotonicsNew York UOld Dominion UORNLPPPLPSIPrinceton USNLThink Tank, Inc.UC DavisUC IrvineUCLAUCSDU ColoradoU MarylandU RochesterU WashingtonU Wisconsin
V1.8
Steven A. SabbaghColumbia University
For the NSTX Research Team
National Tokamak Planning WorkshopSeptember 17-19, 2007
MIT Plasma Science and Fusion Center
Cambridge, MA
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 2
Maintain high N wall-stabilized operation by applying first-principles tokamak physics understanding
Objectives: Advancement of low-A, high beta tokamak plasma devices in support
of an ST development path to sustained fusion generation
• Addresses OFES goal: Configuration Optimization
Applied stability physics understanding applicable to tokamaks in general, leveraged by unique low-A, and high operational regime
• Addresses OFES goal: Predictive Capability for Burning Plasmas
Community discussion - input welcomed (email comments to [email protected])
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 3
Advanced tokamak operation demonstrated in a mega-Ampere class spherical torus
li
N
N/li = 12 68
4
10
wall stabilized
EFIT
BetaN vs. li
0
1
2
3
4
5
6
7
8
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
liSeries2Series3Series4Series5Series6Series7
li
N
N/li = 12 68
4
10
wall stabilized
EFIT
BetaN vs. li
0
1
2
3
4
5
6
7
8
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
liSeries2Series3Series4Series5Series6Series7
High operational space Ultra-high t = 39%, near
unity in core
Broad current and pressure profiles
N > 7, N/li > 11
Wall-stabilized, N/Nno-wall >
50% at highest N
Future research moves forward to demonstrate the reliable maintenance of wall-stabilized state S.A. Sabbagh, et al., Nucl. Fusion 46, 635 (2006).
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 4
MHD research in 2008 - 2013 period separated into several topics
High plasma shaping and global stability
Resistive wall mode physics and stabilization
Dynamic error field correction
Tearing mode / NTM physics
Plasma rotation / non-axisymmetric field-induced viscosity
Mode-induced disruption physics and mitigation
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 5
Access and maintain high t and N at high shaping
Present status / issues Sustained < 2.6, < 0.8; transient = 3 with record
shaping factor, S q95(Ip/aBt) = 41
Highest and S plasmas limited to N ~ 4 < Nno-wall
Plan summary 2008-2013 2008-2010: Operate with upgraded control computer.
Test feedback control using diamagnetic loop sensor and NBI power.
Experiments to extend high S plasmas into wall-stabilized, high N > 6 operating space
2010-2012: Integration of feedback into real-time EFIT, improve strike point control for Li divertor.
2012-2013: real-time MSE w/real-time V for real-time EFIT, feedback using stability models
Goal: sustain stable, high beta operation at very high plasma elongation ~ 3 as a proof-of-principle for ST development and to confirm MHD stability theory in this operating space.
Contributes to: NHTX, ST-CTF development
D.A. Gates, et al., Nucl. Fusion 47, 1376 (2007).
121241
t=275ms
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 6
Low A: key understanding for RWM active/passive stabilization
Plan summary 2008-2013 2008-2011: RWM active stab. sensor,
parameter variation study, investigate underlying stabilization physics
Methods of decreasing possibility of RWM poloidal deformation, investigate SOLC / multiple modes in stabilization
RWM passive stabilization physics research to further examine V, profile, A, i, A, e.g. trapped particle precession resonance (joint XPs)
2008-2009: Design high-n control coil (NCC); adv. stabilization algorithms
2010-2011: n > 1 RWM study during n = 1 stabilization, measure SOLC
2012-2013: non-magnetic sensors, NCC use for stabilization
Goal: Determine RWM passive/active stabilization physics, apply understanding to optimize/increase reliability of active stabilization at low A, to provide greater confidence in physicsused to extrapolate RWM stabilization to future tokamaks, including burning plasma devices.
Contributes to: ITPA MDC-2, ITER issue card RWM-1, USBPO coil design, 2009 milestone
Active n = 1 RWM stabilization in NSTX…
S.A. Sabbagh, et al., Phys. Rev. Lett. 97, 045004
(2006).
FIG. 1
0.40 0.50 0.60 0.70 0.80 0.90t(s)
0.00.51.01.52.0
05
10152005
1015200.00.51.01.5
02468
Shot 120047
0
2
4
6
t(s)
N
IA (kA)
Bpun=1 (G)
Bpun=2 (G)
Brn=1 (ext) (G)
/2 (kHz)
N > N (n=1)no-wall
120047120712
< crit
92 x (1/RWM )
120717 (a)
(b)
(c)
(d)
(e)
(f)
6420840
1.51.00.50.02010
02010
02100.4 0.5 0.6 0.7 0.8 0.9
…can show poloidal
deformation of mode,
stability loss
FIG. 3
0.40 0.50 0.60 0.70 0.80 0.90t(s)
0
10
20
30
400
2
4
6
8
100
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Shot 119755
45o (119761)
315o (119755) 290o (119764)
225o (119770)
negativefeedbackresponse
f
6
4
2
086420
30
20
100
N
/2 (kHz)
Bpun=1 (G)
0.50.4 0.6 0.7 0.8 0.9t (s)
(a)
0.55 0.59 0.63 0.67 0.71 0.75t(s)
02
4
6802468
10120
10
20
300
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6
Shot 120048
0
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Bp n = 1 lower
Br n = 1 lower
Shot 120048(b)
0.590.55 0.63 0.67 0.71 0.75t (s)
6420
840
20100
420
6420
N
/2 (kHz)Bpu,l
n=1 (G)
Bru,ln=1 (G)
Br extn=1 (G)
N collapse
120048bulge
feedback on
FIG. 3
0.40 0.50 0.60 0.70 0.80 0.90t(s)
0
10
20
30
400
2
4
6
8
100
2
4
6
Shot 119755
45o (119761)
315o (119755) 290o (119764)
225o (119770)
negativefeedbackresponse
f
6
4
2
086420
30
20
100
N
/2 (kHz)
Bpun=1 (G)
0.50.4 0.6 0.7 0.8 0.9t (s)
(a)
0.55 0.59 0.63 0.67 0.71 0.75t(s)
02
4
6802468
10120
10
20
300
2
4
6
Shot 120048
0
2
4
6
Bp n = 1 lower
Br n = 1 lower
Shot 120048(b)
0.590.55 0.63 0.67 0.71 0.75t (s)
6420
840
2010
0
420
6420
N
/2 (kHz)Bpu,l
n=1 (G)
Bru,ln=1 (G)
Br extn=1 (G)
N collapse
120048bulge
feedback on0.4 0.5 0.6 0.7 0.8 0.9
t(s)
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 7
0.65s 0.65s
Dynamic Error Field Correction critical to maintain high N
Plan summary 08-13 2008-2012:
investigate sources / physics of dynamic error field, resonant field amplification
implement correction methods n = 1-3
2012-2013: Utilize new NCC to expand capability of DEFC (n 6) to sustain plasma rotation and high N
Goal: Determine sources of dynamically changing error field due to inherent asymmetriesin the device and plasma physics responsible for amplification of these sources. Applytechniques that will dynamically cancel these fields to maintain plasma rotation and stability.
Contributes to: ITER issue card RWM-1, ITER issue card AUX-1
NSTX Record Pulse Length in Ip = 0.9 MA Plasma with combined n = 1 DEFC and n = 3 EFC
J.E. Menard, et al. NSTX XP702 (2007).
n = 1 rotating modesuppressed
Plasma rotation maintained
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 8
Investigate explicit A dependences on tearing stability
Plan summary 2008-2013 2008-2011: Increase simulation
capacity: modified Rutherford equation at low-A, PEST3, rDCON, NIMROD, M3D
Compare sawtooth seeded 2/1, 3/2 with spontaneous modes; compare to higher A. Determine seeding mechanisms.
2010-2012: NTM onset N vs. *, *, V, V shear, compare to higher A
2011-2013: Develop discharges that minimize mode impact. Assess EBWCD results for potential stabilization.
2012-2013: Comparison of NTM experiments to theory/simulation developed
Goal: Generate critical data at low A, high and p, large i to verify tearing mode
physics for burning plasma experiments. Investigate mode impact on , V, fastparticle redistribution; low A operation as being theoretically favorable for stability.Contributes to: ITPA MDC-3, ITPA MDC-4
2/1 onset N vs. toroidal rotation
E.J. Strait, et al., NSTX XP 740 (2007).
N
V (kHz)
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 9
Control V, profile using knowledge of plasma viscosity
Plan summary 2008-2013 2008-2011: Continue testing
viscosity theory from resonant /non-resonant fields; design NCC
Focus on key parameters: i, q, N, V, n; for future devices
2011-2012: 2nd beam line to vary torque at fixed power
2012-2013: Use NCC to test viscosity theories (n 6)
Real-time V control using CHERS sensors, basic sources and sinks of plasma toroidal momentum
2013: real-time V control using additional momentum sources
Attempt momentum input with NCC
Goal: Continue to develop quantitative, first-principles physics models of non-axisymmetricfield-induced plasma viscosity for both resonant and non-resonant field, and apply resultsto create new techniques for imparting toroidal momentum to the plasma.
Contributes to: ITPA MDC-2, ITPA MDC-12, ITER issue card AUX-1
TN
TV
(N m
)
3
4
2
1
00.9 1.1 1.3 1.5
R (m)
measured
theoryt = 0.360s116931
axisTN
TV
(N m
)
3
4
2
1
0
3
4
2
1
00.9 1.1 1.3 1.50.9 1.1 1.3 1.5
R (m)
measured
theoryt = 0.360s116931
axis
Measured d(Ip)/dt profile and theoreticalNTV torque (n = 3 field configuration)
W. Zhu, et al., Phys. Rev. Lett. 96, 225002 (2006).
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 10
Analyze disruption characteristics, causal modes, avoidance
Plan summary 2008-2013 2009-2011: Further characterize
modes that lead to disruptions, operational boundaries
Implement halo current diagnostics, connection between modes and halo currents, scaling of magnitude /peaking with plasma parameters
Simulate thermal and current quench at low A
2011-2012: Detection of impending disruptions based on real-time measurements
2012-2013: Develop disruption mitigation strategies, based on successful detection techniques
Goal: Derive understanding of disruptions by characterizing instabilities that lead to them.Apply understanding to disruption avoidance or control of impact. Analyze disruption effects at low A, high beta by measuring halo current, thermal, and current quench characteristics.
Contributes to: ITER issue card DISR-1Area-normalized (left), Area and li-normalized (right) Ip quench time vs. toroidal Jp (ITER DB)
J.C. Wesley et al., 21st IAEA Fusion Energy Conference (Chengdu, China 2006), paper IT/PI-21.
NSTX
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 11
New capabilities planned to address numerous goals Planned capabilities
2009 - 2013 Non-axisymmetric
control coil (NCC) – at least four applications
• RWM stabilization (n > 1, higher N)
• DEFC with n 6
• ELM mitigation (n = 6)
• Rotation control (n 6; n > 1 propagation)
Non-magnetic RWM sensors; advanced RWM active feedback control algorithms (ITER, etc.)
Alteration of stabilizing plate materials / electrical connections
Scrape-off layer currents (SOLC) / passive plate current measurement
PrimaryPP option
SecondaryPP option
Existingcoils
Proposed Internal Non-axisymmetric Control
Coil (NCC)
RWM with n > 1 RWMobserved
0.22 0.24 0.26 0.28t(s)
-20-10
010200
100200300
010
20300
102030400
204060
02
46
0.18 0.20 0.22 0.24 0.26 0.28t(s)
-20-10
010200
100200300
0
10
200
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20300
102030
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46
114147
FIG. 1
114452
N
FP
|Bp|(n=1)
(G)(G)
(G)
|Bp|(n=2)
|Bp|(n=3)
Bp(n=1)(deg)
|Br|(n=1)(ext.)
Bz(G
) (f<40 kHz, odd-n)
n=2,3
n=1 no-wall unstable
0.240.22 0.26 0.28t(s)
(Sabbagh, et al., Nucl. Fusion 46, 635 (2006). )
NSTX National Tokamak Planning Workshop 2007 – NSTX MHD 12
Macroscopic Stability Research Timeline (Sept. 2007)5 Year Plan time period
08 09 10 11 12 13FY07 14
control; Halo current diagnostics, fast IR for PFC disrupt. loads; disrupt. detection
Greater resolution and real-time MSE; real-time rotation for V control
Advanced RWM control algorithms; J profile control
Develop NIMROD and M3D modeling of NTM, disruptions, RWM at low A
Physics model for DEFC at high ; optimize DEFC with RWM coil
FIDA for fast ion redistribution; fast IR for disruption studies
Ph
ysic
sT
oo
ls
shaping N control w/stability models
N control rtEFIT, strike point control
Operate N > 6 with High S; N control
RWM
outage outage
Non-mag RWM detection; control
Role of n > 1, stabilize RWM w/NCC
Assess controlIncorporate measured SOLC in models
Role of SOLC, adv. RWM control design
Opt. active RWM control varied params, V; mode deform.
RWM stab. physics (i,V,A, multi-modes); NCC design
non-mag. RWM controltwo toroidal SXR arrays; non-mag. RWM detect.
SOLC measurement; passive plate currents; VALEN SOLC; > Langmuir coverage
High f NCC w/audio ampsNCC install
DEFC
NTM
V physics
Disruptions
n=1,2,3 correction with NCC
Test models vs. low A XPs; minimize plasma impactModeling at low A; seeded v. non-seeded
physics
V1.1
NTV using NCC; Real-time V controlNTV physics, i, n=2, INTV, future devices, NCC design
disrupt. detection; mitigationCharacterize disruption/modes; low A disrupt. simulation