High harmonic electron cyclotron resonance heating in the large helical device

摘要

During the initial experimental phase, LHD, a stellarator of the heliotron/torsatron variety presently under construction, will operate at a magnetic field lower than the nominal one. In this scenario, the frequency of the available gyrotrons(chosen in view of second harmonic heating at full field operation)will be resonant with the third or the fourth harmonic of the electron gyrofrequency. The aim of this article is to analyse the electron cyclotron resonance heating(ECRH)at these high Harmonics. By using linear absorption theory, together with transport predictions, good absorption Is found over a wide density range for third harmonic heating.