Physics Basis of FIRE Next Step Burning Plasma Experiment

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Physics Basis of FIRE Next Step Burning Plasma
Experiment

• Charles Kessel
• Princeton Plasma Physics Laboratory
• U.S.-Japan Workshop on Fusion Power Plant Design,
  University of Tokyo
• March 29-31, 2001

http//fire.pppl.gov
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Goals of the FIRE Study
Using the high field compact tokamak, produce
burning plasmas with Q gt 5-10 over pulse lengths
gt 2 current diffusion times, to study and resolve
both standard and advanced tokamak burning plasma
physics issues, for 1B
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FIRE Has Many Features Similar to ARIES Tokamaks
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FIRE Looks Like a Scale Model of ARIES-AT
Nw 3 MW/m2 Pfus 12 MW/m3
Nw 3.3 MW/m2 Pfus 5.3 MW/m3
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FIRE Can Access Various Pulse Lengths by Varying
BT
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FIREs Divertor Must Handle Attached(25 MW/m2)
and Detached(5 MW/m2) Operation
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FIREs Divertor is Designed to Withstand Large
Eddy Current and Halo Current Forces
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FIRE Must Handle Disruptions
VDE Simulation with 3 MA/ms Current Quench
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FIRE Has Several Operating Modes Based on Present
Day Physics

• Reference ELMing H-mode
• B10 T, Ip6.5 MA, Q5, t(pulse)18.5 s
• High Field ELMing H-mode
• B12 T, Ip7.7 MA, Q10, t(pulse)12 s

• AT Mode Reverse Shear with fbsgt50
• B8.5 T, Ip5.0 MA, Q5, t(pulse)35 s
• Long Pulse DD AT Mode and H-mode
• B4 T, Ip2.0 MA, Q0, t(pulse)gt200 s

FIRE can study both burning AND long pulse plasma
physics in the same device
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Progress Toward ARIES-like Plasmas Requires A
Series of Steps
1) stabilize NTMs 2) stabilize n1 RWM 3)
stabilize ngt1 RWMs each step with higher
fbs each step with more profile control
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FIRE is Examining Ways to Feedback Control
RWM/Kink Modes
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FIRE Must Satisfy Present Day Physics Constraints
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FIRE Can Access Most of the Existing H-mode
Database
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FIREs Performance With Projected Confinement
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FIRE Is Being Designed to Access Higher b AT
Plasmas
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Plasma Response to Paux Modulation
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Plasma Response to Fueling Modulation
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Divertor Pumping Strongly Affects Plasma Burn
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TSC Simulation of FIRE Burning AT Discharge
Ip5 MA, Bt8.5 T, bN3.0, li(3)0.4, n/nGr0.7,
H(y,2)1.15, PLH20 MW, PICRF18 MW, n(0)/ltngt1.45
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TSC Simulation of FIRE Burning AT Discharge
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A Burning Device Like FIRE Must Validate
Assumptions Made in Power Plant Studies Like ARIES

• Control of current, n, and T profiles
• Develop methods to mitigate/avoid disruptions
• Demonstrate energetic particle effects are benign
• All in a plasma with significant alpha particle
  heating

• Power and particle handling in the
  divertor/SOL/first wall
• Stabilization of NTMs
• Stabilization of RWM/Kink modes
• Large bootstrap fraction plasmas with external CD

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The FIRE Design is Evolving

• What can the machine do?
• Q
• Pulse length
• T and n variations
• Heating/fueling/pumping/current drive
• What is the impact of physics uncertainties?
• Scaling of tE
• Scaling of Pth(L to H)

• NTM b-limit
• Density limit
• Particle confinement tp/tE
• What is machine flexibility to examine physics
  issues?
• Burn control
• AE, energetic particles
• Sawteeth, other MHD
• AT profile interactions (p(r), j(r), c(r))