Advanced Tokamak Scenarios

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Advanced Tokamak Scenarios for FIRE and Alcator
C-Mod
Charles Kessel and Dale Meade
ITPA Steady-State Energetic-Particle Task Group
Meeting St. Petersburg, Russia July 15, 2003
http//fire.pppl.gov
FIRE Collaboration
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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How Hard should the AT be Pushed?
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FIRE Parameters Approach ARIES-RS
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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(RN) m 1 sawtooth Model - Jardin
etal other effects to be added - Jardin
FIRE, the Movie
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0-D Power/Particle Balance Identifies Operating
Space for FIRE - AT

• Heating/CD Powers
• ICRF/FW, 30 MW
• LHCD, 30 MW
• Using CD efficiencies
• ?(FW)0.20 A/W-m2
• ?(LH)0.16 A/W-m2
• P(FW) and P(LH) determined at r/a0 and r/a0.75
• I(FW)0.2 MA
• I(LH)Ip(1-fbs)
• Scanning Bt, q95, n(0)/ltngt, T(0)/ltTgt, n/nGr, ?N,
  fBe, fAr

• Q5
• Constraints
• ?flattop/?CR determined by VV nuclear heat (4875
  MW-s) or TF coil (20s at 10T, 50s at 6.5T)
• P(LH) and P(FW) max installed powers
• P(LH) P(FW) Paux
• Q(first wall) lt 1.0 MWm-2 with peaking of 2.0
• P(SOL) - Pdiv(rad) lt 28 MW
• Qdiv(rad) lt 8 MWm-2

Generate large database and then screen for
viable points
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FIREs Q 5 AT Operating Space

• Access to higher ?flat/?j decreases at higher ?N,
  higher Bt, and higher Q, since ?flat is set by VV
  nuclear heating

• Access to higher radiated power fractions in the
  divertor enlarges operating space significantly

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FIREs AT Operating Space
Q 5 - 10 accessible ?N 2.5 - 4.5
accessible fbs 50 - 90 accessible tflat/tCR
1 - 5 accessible
If we can access.. H98(y,2) 1.2 -
2.0 Pdiv(rad) 0.5 - 1.0 P(SOL) Zeff 1.5 -
2.3 n/nGr 0.6 - 1.0 n(0)/ltngt 1.5 - 2.0
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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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Tests of Self- Organization before DT
Transport
Self-heating (90)
Bootstrap (90)
An advanced reactor plasma must be largely
self-organized with minimal external control.
We shouldnt wait until first DT on a BPX
(2015-2018) to determine the conditions for a
tokamak to self-organize, and an access path.
There is 15 years for - a focused effort
on an experimental simulation (Paux C
n2T2) - a comprehensive computer simulation of
an advanced BP
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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.
Continued development of integrated simulations
and integrated experiments is needed. A
self-organization experiment would be an
important result.
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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."