Advanced Tokamak Modes in FIRE

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Advanced Tokamak Modes in FIRE
Dale Meade, Charles Kessel and Steve Jardin
ITPA MHD Task Group Meeting St. Petersburg,
Russia July 15, 2003
FIRE Collaboration
http//fire.pppl.gov
AES, ANL, Boeing, Columbia U., CTD, GA, GIT,
LLNL, INEEL, MIT, ORNL, PPPL, SNL, SRS, UCLA,
UCSD, UIIC, UWisc,
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Fusion Ignition Research Experiment (FIRE)

• R 2.14 m, a 0.595 m
• B 10 T, ( 6.5 T, AT)
• Ip 7.7 MA, ( 5 MA, AT)
• PICRF 20 MW
• PLHCD 30 MW (Upgrade)
• Pfusion 150 MW
• Q 10, (5, AT)
• Burn time 20s (2 tCR-Hmode)
• 40s (lt 5 tCR-AT)
• Tokamak Cost 350M (FY02)
• Total Project Cost 1.2B (FY02)

1,400 tonne
Mission to attain, explore, understand and
optimize magnetically-confined fusion-dominated
plasmas
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Characteristics of FIRE

• 40 scale of ARIES plasma xsection
• kx 2.0, dx 0.7, ripple 0.3
• All metal PFCs
• Actively cooled W divertor
• Be tile FW, cooled between shots
• T inventory TFTR
• Close Fitting Copper Stabilizers
• Position control coils btwn VV shells
• RWM coils in the first wall
• 75 -115 MHz ICRF for heating and on-axis CB, 5
  GHz LH for off-axis CD, 170 GHz ECCD for NTM
  stabilization

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FIRE Plasma Regimes
H-Mode AT(ss) ARIES-RS/AT R/a 3.6 3.6
4 B (T) 10 6.5 8 - 6 Ip (MA)
7.7 5 12.3-11.3 n/nG 0.7 0.85 1.7-0.85 H(
y,2) 1.1 1.2 1.7 0.9 - 1.4 bN 1.8
4.2 4.8 - 5.4 fbs , 25 77 88 -
91 Burn/tCR 2 3 - 5 steady
Operating Modes Elmy H-Mode Improved
H-Mode Reversed Shear AT - OH assisted -
steady-state (100 NI)
H-mode facilitated by dx 0.7, kx 2, n/nG
0.7, DN reduction of Elms.
AT mode facilitated by strong shaping, close
fitting wall and RWM coils.
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Simulation of a Standard H-mode in FIRE - TSC
CTM GLF23 m 1 sawtooth Model - Jardin et
al other effects to be added - Jardin et al
FIRE, the Movie
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How Hard should the AT be Pushed?
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Updating FIRE AT Equilibrium Targets Based on
TSC-LSC Equilibrium
TSC-LSC equilibrium Ip4.5 MA Bt6.5 T q(0)3.5,
qmin2.8 ?N4.2, ?4.9, ?p2.3 li(1)0.55,
li(3)0.42 p(0)/?p?2.45 n(0)/?n?1.4 Stable
n? Stable n1,2,3 with no wall
vV/Vo
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Steady-State High- b Advanced Tokamak Discharge
on FIRE
0 1 2
3 4
time,(current redistributions)
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q Profile is Steady-State During Flattop, t10 -
41s 3.2 tCR
li(3)0.42
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Neo-Classical Tearing Modes for FIRE AT Modes
Target Bt6.5-7 T for NTM control, to utilize 170
GHz from ITER RD Must remain on LFS for
resonance and use O-mode, due to high Bt ECCD
efficiency?? (trapping)
Can we avoid NTMs with j(?) and qgt2.0 or do we
need to suppress them??
Ro
Roa
Bt6.5 T
?
fce182
fce142
170 GHz
Ro
Roa
Bt7.5 T
?
?
fce210
fce164
200 GHz
Ro
Roa
Bt8.5 T
?
fce190
fce238
Can we rely on OKCD to suppress NTMs far
off-axis on LFS versus ECCD ?? (enhanced Ohkawa
affect at plasma edge)
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J. Decker, APS 2002,MIT
OKCD allows LFS EC deposition, with similar A/W
as ECCD on HFS
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Comments on ECCD in FIRE

• ASDEX-U shows that 3/2 island is suppressed for
  about 1 MW of power with IECCD/Ip 1.6, giving
  0.013 A/W
• Ip0.8 MA and ?N2.5
• DIII-D shows that 3/2 island is suppressed for
  about 1.2-1.8 MW with jEC/jBS 1.2-2.0
• Ip1.0-1.2 MA, ?N2.0-2.5
• OKCD analysis of Alcator-CMOD gives about 0.0056
  A/W
• FIREs current requirement should be about 15
  times higher than ASDEX-U (scaled by Ip and ?N2)
• Need about 200 kA, which would require about 35
  MW?? Early detection reduces power alot according
  to ITER
• Do we need less current for 5/2 or 3/1, do we
  need to suppress them??
• Is 170 GHz really the cliff in EC technology??

MIT, short pulse results
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FIRE EC Geometry
?ce ?
n(0)4.5?1020 f pe9?vn
Rays are bent as they ? approaches ?pe
EC launcher
Rays must be launched with toroidal
directionality for CD
?pe gt ? cutoff for 170 GHz
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Disruptions in FIRE

• Adhere to ITER disruption guidelines - any major
  modifications envisioned?
• ?quench 0.1-0.5 ms
• dIp/dt(max) 3 MA/ms
• Ihalo(max) 0.25 ? Ip (peaking factors are to be
  used in Opera or VV analysis)
• Vertical disruption modeled by TSC to give
  dynamics and eddy currents
• dIp/dt 3MA/ms
• Ihalo 2 MA
• Near midplane disruption
• dIp/dt 3 MA/ms
• Ihalo 2 MA
• Structure model (TSC-simplified,
  Opera-Sandia-Ulrickson, ORNL-Nelson)

• Are neutrally stable DN disruptions different?,
  less violent?,less frequent?
• Could a fast internal coil system help
  ameliorate VDE disruptions?

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RD Needed for Advanced Tokamak Burning
Plasma Scaling of energy and particle
confinement needed for projections of performance
and ash accumulation. Benchmark codes using
systematic scans versus density, triangularity,
etc. Continue RWM experiments to test theory
and determine hardware requirements. Determine
feasibility of RWM coils in a burning plasma
environment. Improve understanding of
off-axis LHCD and ECCD including effects of
particle trapping, reverse CD lobe on edge
bootstrap current and Ohkawa CD. Develop
techniques for NTM stabilization in H-Mode (10T)
and AT(6.5T). Development of a
self-consistent edge-plasma-divertor model for W
divertor targets, and incorporation of this model
into core transport model. Determine effect
of high triangularity and double null on
confinement, b-limits, Elms, and disruptions.
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Latest News about US Fusion Funding
House of Representatives Energy and Water SC
Appropriations - July 9,03
"The Committee recommendation for fusion energy
sciences is 268,110,000, an increase of
10,800,000 over the budget request. The
Committee is cautiously supportive of the
Administration's proposal to re-engage in
the International Thermonuclear Experimental
Reactor (ITER) project, but is disappointed that
the budget request provides 12,000,000 in
funding for the U.S. ITER effort only at the
expense of displacing ongoing domestic fusion
research. The additional 10,800,000 includes
4,000,000 for burning plasma experiments,
including support for ITER and for the
domestic FIRE project, 5,200,000 for fusion
technology, and 1,600,000 for advanced design
and analysis work. If the Department intends to
recommend ITER participation in the fiscal year
2005 budget request, the Committee expects the
Department will so so without harm to domestic
fusion research or to other programs in the DOE
Science budget."