RF Heating and CD at low frequencies (below all ion cyclotron harmonic resonances) C.K. Phillips, J. Hosea, E. Valeo, J.R. Wilson PPPL P. Bonoli, Y. Lin, R. Parker, M. Porkolab, J. Wright and S. Wukitch PSFC-MIT C-Mod 2007 Ideas Forum

Overview GOAL: -Explore RF heating and current drive in the low frequency regime by launching fast waves with f ≤ fci for all ions PURPOSE: -potential applications in ITER / reactors -unique C-Mod capability: high BT and low RF frequency APPROACH: -launch fast waves at 40 MHz into D plasma with BT > 7T -use power modulation / power notch to measure absorption profile -possibly preheat with lower hybrid to improve electron damping -possibly detect shear Alfven wave with PCI - half a day run required? C-Mod 2007 Ideas Forum

With 40 MHz and BT > 7T, almost all possible ion resonances are out of the machine LFS edge of plasma C-Mod 2007 Ideas Forum

Simulations indicate that Alfvén Wave heating regime is accessible on C-Mod at 8T with 40 MHz TORIC mock-up of low frequency regime: Use H minority test case at 5.3T but lower frequency to 25 MHz coherent mode is probably kinetic shear Alfvén wave qualitatively consistent with earlier 1D studies with METS at 8T, 40 MHz mode damps on electrons Possibly detectable with PCI? C-Mod 2007 Ideas Forum

C-Mod 2007 Ideas Forum