PPPL-4059 is available in pdf format (692 KB).

Edge Minority Heating Experiment in Alcator C-Mod

Authors: S.J. Zweben, J.L. Terry, P. Bonoli, R. Budny, C.S. Chang, C. Fiore, G. Schilling, S. Wukitch, J. Hughes, Y. Lin, R. Perkins, M. Porkolab, and the Alcator C-Mod Team

Date of PPPL Report: March 2005

To be presented at: the 16th Topical Conference on Radio-frequency Power in Plasmas, 11-13 April 2005, Park City, Utah

An attempt was made to control global plasma confinement in the Alcator C-Mod tokamak by applying ion cyclotron resonance heating (ICRH) power to the plasma edge in order to deliberately create a minority ion tail loss. In theory, an edge fast ion loss could modify the edge electric field and so stabilize the edge turbulence, which might then reduce the H-mode power threshold or improve the H-mode barrier. However, the experimental result was that edge minority heating resulted in no improvement in the edge plasma parameters or global stored energy, at least at power levels of PRF ≤ 5.5 MW. A preliminary analysis of these results is presented and some ideas for improvement are discussed.