Confinement, Transport and Turbulence Properties of NSTX Plasmas
Wall Stabilized Operation in High Beta NSTX Plasmas
11
NSTX SAS - FEC ‘04 S. A. Sabbagh 1 , A.C. Sontag 1 , R. E. Bell 2 , J. Bialek 1 , D.A. Gates 2 ,A. H. Glasser 3 , B.P. LeBlanc 2 , J.E. Menard 2 , W. Zhu 1 , M.G. Bell 2 , T.M. Biewer 2 , A. Bondeson 4 , C.E. Bush 5 , J.D. Callen 6 , M.S. Chu 7 , C. Hegna 6 , S. M. Kaye 2 , L. L. Lao 7 , Y. Liu 4 , R. Maingi 5 , D. Mueller 2 , K.C. Shaing 6 , D. Stutman 8 , K. Tritz 8 , C. Zhang 9 Wall Stabilized Operation in High Beta NSTX Plasmas 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 JAERI Ioffe Inst TRINITI KBSI KAIST ENEA, Frascati CEA, Cadarache IPP, Jülich IPP, Garching U Quebec 20 th IAEA Fusion Energy Conference 1-6 November 2004 Vilamoura, Portugal 1 Department of Applied Physics, Columbia University, New York, NY, USA 2 Plasma Physics Laboratory, Princeton University, Princeton, NJ, USA 3 Los Alamos National Laboratory, Los Alamos, NM, USA 4 Institute for Electromagnetic Field Theory, Chalmers U., Goteborg, Sweden 5 Oak Ridge National Laboratory, Oak Ridge, TN, USA 6 University of Wisconsin, Madison, WI, USA 7 General Atomics, San Diego, CA, USA 8 Johns Hopkins University, Baltimore, MD, USA 9 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
description
Supported by. Wall Stabilized Operation in High Beta NSTX Plasmas. 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 - PowerPoint PPT Presentation
Transcript of Wall Stabilized Operation in High Beta NSTX Plasmas
NSTX SAS - FEC ‘04
S. A. Sabbagh1, A.C. Sontag1, R. E. Bell2, J. Bialek1, D.A. Gates2,A. H. Glasser3, B.P. LeBlanc2, J.E. Menard2, W. Zhu1, M.G. Bell2, T.M. Biewer2, A. Bondeson4, C.E. Bush5, J.D. Callen6, M.S. Chu7, C. Hegna6, S. M. Kaye2, L. L. Lao7, Y. Liu4, R. Maingi5, D. Mueller2, K.C. Shaing6, D. Stutman8, K. Tritz8, C. Zhang9
Wall Stabilized Operation in High Beta NSTX Plasmas
Supported by
Columbia UComp-X
General AtomicsINEL
Johns Hopkins ULANLLLNL
LodestarMIT
Nova PhotonicsNYU
ORNLPPPL
PSISNL
UC DavisUC Irvine
UCLAUCSD
U MarylandU New Mexico
U RochesterU Washington
U WisconsinCulham Sci Ctr
Hiroshima UHIST
Kyushu Tokai UNiigata U
Tsukuba UU Tokyo
JAERIIoffe Inst
TRINITIKBSI
KAISTENEA, Frascati
CEA, CadaracheIPP, Jülich
IPP, GarchingU Quebec
20th IAEA Fusion Energy Conference1-6 November 2004Vilamoura, Portugal
1Department of Applied Physics, Columbia University, New York, NY, USA2Plasma Physics Laboratory, Princeton University, Princeton, NJ, USA
3Los Alamos National Laboratory, Los Alamos, NM, USA4Institute for Electromagnetic Field Theory, Chalmers U., Goteborg, Sweden5Oak Ridge National Laboratory, Oak Ridge, TN, USA6University of Wisconsin, Madison, WI, USA7General Atomics, San Diego, CA, USA8Johns Hopkins University, Baltimore, MD, USA9Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
NSTX SAS - FEC ‘04
Wall stabilization physics understanding is key to sustained plasma operation at maximum
• High t = 39%, N = 6.8 reached
N
li
N/li = 12 68
4
10
wall stabilized
• Global MHD modes can lead to rotation damping, collapse
• Physics of sustained stabilization is applicable to ITER
• Operation with N/Nno-wall > 1.3 at
highest N for pulse >> wall
-25-20-15-10
-505
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
N
01234567
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
DCON
W
0
10
20
0.6 0.70.50.40.30.20.10.0t(s)
n=1 (no-wall)n=1 (wall)
112402
wall stabilized
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
EFIT
core plasma rotation(x10 kHz)
NSTX SAS - FEC ‘04
Theory provides framework for wall stabilization study
• This talk: Resistive Wall Mode physics RWM toroidal mode spectrum Critical rotation frequency, crit
Toroidal rotation damping Resonant field amplification (RFA)
• Theory Ideal MHD stability – DCON (Glasser) Drift kinetic theory (Bondeson – Chu) RWM dynamics (Fitzpatrick – Aydemir)
2**
211ˆ11ˆˆˆˆ mdmdSmdsii
plasma inertia dissipation mode strength wall response wall/edge coupling
S* ~ 1/wall
0.0 0.5 1.0 1.5-1.0
-0.5
0.0
0.5
1.0
mo
de
str
eng
th s
ideal wall limit
no-wall limit*=
Fitzpatrick-Aydemir (F-A)stability curves
plasma rotation
Phys. Plasmas 9 (2002) 3459
stable
wall stabilized
stable
NSTX SAS - FEC ‘04
Unstable RWM dynamics follow theory
• Unstable n=1-3 RWM observed ideal no-wall unstable
at high N
n > 1 theoretically less stable at low A
• F-A theory / experiment show mode rotation can
occur during growth growth rate, rotation
frequency ~ 1/wall
• << edge > 1 kHz RWM phase velocity
follows plasma flow n=1 phase velocity
not constant due to error field
• Low frequency tearing modes absent
growth w/o mode rotation mode rotation during growth
N
|Bp|(n=1)
(G)
(G)
(G)
|Bp|(n=2)
|Bp|(n=3)
Bp(n=1)(deg
)B
z(G
) (f<40 kHz, odd-n)
n=2,3
n=1 no-wall unstable
n=1-3 no-wall unstable
0.22 0.24 0.26 0.28t(s)
-20-10010200
100200300010
20300102030400204060
02
46
0.18 0.20 0.22 0.24 0.26 0.28t(s)
-20-10010200
1002003000
10
20010
20300102030
02
46
114147
FIG. 1
114452
moderotation
mode growth
NSTX SAS - FEC ‘04
• Visible light emission is toroidally asymmetric during RWM
• DCON theory computation displays mode uses experimental equilibrium reconstruction includes n = 1 – 3 mode spectrum uses relative amplitude / phase of n spectrum
measured by RWM sensors
Camera shows scale/asymmetry of theoretical RWMRWM with Bp = 92 G
Before RWM activity
114147t = 0.250s
114147t = 0.268s
Theoretical B (x10) with n=1-3 (DCON)
114147 114147
(interior view)(exterior view)
NSTX SAS - FEC ‘04
0.08
0.06
0.04
0.02
0.000.270 0.275 0.280 0.285 0.290 0.295
0.270 0.275 0.280 0.285 0.290 0.295
0.270 0.275 0.280 0.285 0.290 0.295
0.08
0.06
0.04
0.02
0.00
0.08
0.06
0.04
0.02
0.00
0.08
0.06
0.04
0.02
0.000.270 0.275 0.280 0.285 0.290 0.295
0.270 0.275 0.280 0.285 0.290 0.295
0.270 0.275 0.280 0.285 0.290 0.295
0.08
0.06
0.04
0.02
0.00
0.08
0.06
0.04
0.02
0.00
0.08
0.06
0.04
0.02
0.000.270 0.275 0.280 0.285 0.290 0.295
0.270 0.275 0.280 0.285 0.290 0.295
0.270 0.275 0.280 0.285 0.290 0.295
0.08
0.06
0.04
0.02
0.00
0.08
0.06
0.04
0.02
0.00
Chord 3
Chord 4
Chord 5
Bay G array (0 deg)Bay J array (90 deg)
Inte
nsity
(ar
b)
• Experiment / theory show RWM not edge localized Supported by
measured Te
114024, t=0.273sN = 5
0.27 0.28 0.29
8
4
0
6
4
0
6
4
0
t(s)
Inte
nsity
(ar
b)In
tens
ity (
arb)
0.0 0.5 1.0 1.5 2.0R(m)
2
1
0
-1
-2
Z(m
)
35 4
RWM growth
2
1
0
0.0 0.2 0.4 0.6 0.8 1.0
DCON n = 1 modedecomposition
n
(arb
)
m=34
56
USXR separated by 90 degrees
n = 0.13
n = 0.4
Soft X-ray emission shows toroidal asymmetry during RWM
2
2
6
2
n = 0.24
m=2
n:0.13 0.24
m=1
0.4
NSTX SAS - FEC ‘04
q1 2 3 4 5
/
A
0.5
0.4
0.3
0.2
0.1
0.0
stabilized1/(4q2)not stabilized
Experimental crit follows Bondeson-Chu theory
• Experimental crit
stabilized profiles: >N
no-wall (DCON)
profiles not stabilized cannot maintain > N
no-wall
regionsseparated by A =1/(4q2)
• Drift Kinetic Theory Trapped particle
effects significantly weaken stabilizing ion Landau damping
Toroidal inertia enhancement more important
• Alfven wave dissipation yields crit = A/(4q2)
/A(q,t) profiles
Phys. Plasmas 8 (1996) 3013
NSTX SAS - FEC ‘04
/
A crit follows F-A theory with neoclassical viscosity
q95
2 4 6 8 10
0.06
0.05
0.04
0.03
0.02
0.01
0.00
stabilized1/(4q2)not stabilized
/A in F-A inertial layer (edge) • Experimental crit
stabilized points: >N
no-wall (DCON)
points not stabilized cannot maintain > N
no-wall regionsseparated by
A =1/(4q2)
• F-A Theory Standard F-A theory
has crit ~ 1/q neoclassical viscosity
includes toroidal inertia enhancement (K. Shaing, PoP 2004)
• yields crit ~ 1/q2
NSTX SAS - FEC ‘04
Plasma rotation damping described by NTV theory
• Evolution detail differs for other modes no momentum transfer across rational surfaces no rigid rotor plasma core (internal 1/1 mode)
0
5
10
15
20
25
30
0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6
t=0.265576
t=0.275576
113924
1.0 1.2 1.4 1.6R(m)
/
2 (
kHz) 25
20
10
15
5
Td (
N m
-2)
0.40.30.20.10.0
-0.1-0.2
0
t = 0.276s
TNTV
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.9 1 1.1 1.2 1.3 1.4 1.5 1.6
0
10
20
30
40
0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6
t=0.225729
t=0.235729
t=0.255729
40
30
20
10114452
/
2 (
kHz) t(s)
0.2260.2360.256
see EX/P2-26 Menard
theory
• Neoclassical toroidal viscosity (NTV) ~ B2*Ti0.5
• Rapid, global damping observed during RWM Edge rotation ~ 2kHz maintained Low frequency tearing modes absent
full rotation evolution
1.0 1.2 1.4 1.6R(m)
0.8
t(s)0.2660.276
initial rotation evolution
measured-R2(d/dt)
axis edge
NSTX SAS - FEC ‘04
Resonant Field Amplification increases at high N
• Plasma response to applied field from initial RWM stabilization coil pair AC and pulsed n = 1 field
• RFA increase consistent with DIII-D
• Stable RWM damping rate of 300s-1 measured
N
Nno-wall
Initial RWM stabilization coils
Sensors
Completed coils will be used to suppress RFA, stabilize RWM, sustain high
(n = 1)
0
0.2
0.4
0.6
4.0 4.5 5.0 5.5 6.0
Pla
sma
re
sp/a
pp
lied
fie
ldpl
asm
a B
p / a
pplie
d B
p
NSTX SAS - FEC ‘04
Wall stabilization research at low aspect ratio illuminates key physics for general high operation
• Plasma t = 39%, N = 6.8, N/li = 11 reached; N/Nno-wall > 1.3
• Unstable n = 1-3 RWMs measured (n > 1 prominent at low A)
• Critical rotation frequency ~ A/q2 strongly influenced by toroidal inertia enhancement (prominent at low A)
• Rapid, global plasma rotation damping mechanism associated with neoclassical toroidal viscosity
• Resonant field amplification of stable RWM increases with increasing N (similar to higher A)
• Evidence for AC error field resonance observed (see poster)
• Effect of rotation on equilibrium reconstruction evaluated (see poster)
Completed RWM active stabilization coil to be used for research in 2005
