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Physics Analysis and Flexibility Issues for FIRE. S. C. Jardin with input from C.Kessel, J.Mandrekas, D.Meade, and the FIRE team. NSO PAC-2 Meeting January 17-18, 2001. Recent FIRE Physics Activities. Since the last PAC meeting: UFA Burning Plasma Workshop
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Physics Analysis and Flexibility Issues for FIRE S. C. Jardin with input from C.Kessel, J.Mandrekas, D.Meade, and the FIRE team NSO PAC-2 Meeting January 17-18, 2001
Recent FIRE Physics Activities Since the last PAC meeting: • UFA Burning Plasma Workshop • MHD and Energetic Particle studies • Transport Studies • TSC perturbation studies and scenario development • SCIDAC Proposal Development • MHD in a burning plasma • Nonlinear GK turbulent transport simulations • Development of AT Modes for FIRE • Disruption Studies for Engineering Analysis
Outline • Lower beta operating modes with Q=10 • Perturbation Studies • Long Pulse AT modes • Future Directions Kessel • More on AT Modes • Disruptions Studies
Guidelines for Predicting Plasma Performance Confinement (Elmy H-mode) ITER98(y,2): E = 0.144 I0.93 R1.39 a0.58 n200.41 B0.15 Ai0.19 0.78 P heat-0.69 H(y,2) Density Limit: n20 < 0.75 nGW = 0.75 IP/a2 H-Mode Power Threshold: Pth > (2.84/Ai) n200.58 B0.82 R a0.81
High Field: H ~ 1.0 (12 T, 7.7 MA) Low Field: H ~ 1.2 (10 T, 6.5 MA) total total a-heating a-heating ICRF ICRF Time (sec) Time (sec) N < 2 N < 2.8 Q > 10 for 9 sec Q > 10 for 18 sec
TSC Simulation of Low N high Q operating point at BT = 12T, IP=7.7MA, H~1 Note: Q ~ 12-20 Max PAUX 15MW N ~ 1.5 N time
Example of Perturbation Study that can be done on FIRE: ICRF heating power increased by 5 or 10MW for 6 sec BT=10T, IP = 6.4 MA, H(y,2) = 1.2 Shows that fusion power amplifies ICRF power over a wide range of input powers
Identification of AT Targets for FIRE • Long pulse AT modes are targeted to operate at reduced field (8.5T) for about 40 sec ( > 3 Skin Times) • We can project backwards from Standard Operating Modes to get requirements on N and H(y,2) for AT modes: Stored Energy: W ~ B2 ~ NIB Energy Confiment time: E ~ H(y,2) IP.93 n.41 BT.15 ~ H(y,2) IP1.34 BT.15
Q=5, BT=10,IP=6.44, H=1, N=2.1 base case W ~ B2 ~ NIB q95 The operating points on this graph will have the same stored energy for the N values shown on the contours. No wall n=1 stab AT rule* need 2.8 3.45 2.8 3.2 3.5 3.5 3.7 3.2 2.5 3.6 2.3 2.9 3.1 3.1 3.4 2.7 *AT rule: lower of 4i and 1.15 N
Q=5, BT=10,IP=6.44, H=1, N=2.1 base case E ~ H(y,2) IP.93 n.41 BT.15 ~ H(y,2)IP1.34 BT.15 The operating points on this graph will have the same energy confinement times for the H(y,2) values shown on the contours. AT modes need H factor in range 1.2 – 1.6 for same confinement time in sec.
Physics Question: Role of the m=1 mode • 3D Extended MHD simulation taking part as part of the SCIDAC initiative will study the m=1 mode in a burning plasma • Proper physics description must take into account: • energetic particle drive, • kinetic stabilization, • 2-fluid effects, and • non-linear saturation mechanism • This is one of the major thrusts of the 3D macroscopic simulations communities..similar to turbulent transport simulations in transport community • FIRE will provide critical data point for code benchmarking and hence for extrapolations
Physics question: NTM • neoclassical tearing mode sets limits in many long-pulse discharges • scaling of this to new devices largely result of empirical fitting of quasi-linear formula • this is another major thrust of 3D macroscopic modeling effort • active feedback looks feasible • FIRE will provide critical data point (From LaHaye, Butter, Guenter, Huysmans, Marashek, and Wilson)
Summary • FIRE should have considerable flexibility to demonstrate high Q operation at a range of N values down to ~1.5 at 12T • Families of AT modes can be generated with same W and E as baseline operating modes • What science will we learn (MHD area)? • How does core self-organize with ’s and m=1 mode? • How does edge self-organize with bootstrap and ELMs • How does interior self-organize with NTM, at new (*,*) • How well can our codes predict these nonlinear events ?