Investigations of Low and Moderate Harmonic Fast Wave Physics on CDX-U
Authors: J. Spaleta, R. Majeski, C.K. Phillips, R.J. Dumont, R. Kaita, V. Soukhanovskii, L. Zakharov
Date of PPPL Report: July 2003
Presented at: the 15th Topical Conference on Radio Frequency Power in Plasmas, Grand Teton National Park, Wyoming, 19-21 May 2003; AIP to publish conference proceedings
Third harmonic hydrogen cyclotron fast wave heating studies are planned in the near term on CDX-U to investigate the potential for bulk ion heating. In preparation for these studies, the available radio-frequency power in CDX-U has been increased to 0.5 MW. The operating frequency of the CDX-U radio-frequency transmitter was lowered to operate in the range of 8-10 MHz, providing access to the ion harmonic range 2W ~ 4W in hydrogen. A similar regime is accessible for the 30 MHz radio-frequency system on the National Spherical Torus Experimennt (NSTX), at 0.6 Tesla in hydrogen. Preliminary computational studies over the plasma regimes of interest for NSTX and CDX-U indicate the possibility of strong localized absorption on bulk ion species.