Parametric decay of a fast wave to two electromagnetic slow waves at half the pump frequency

Abstract

The parametric decay process of a fast wave at the ion-cyclotron range of frequencies (ICRF) into two electromagnetic slow (or ordinary) waves is considered. It is shown that in the dipole approximation of the pump wave, the decay process is possible at around half the frequency of the pump. Plasmas of interest that are susceptible to this decay process include deuterium–hydrogen (D–H), deuterium–helium 3 (D–He3), and deuterium–tritium (D–T) plasmas. It is shown that the growth rate may approach a few percent of the pump frequency at the edge, and may thus lead to edge electron heating.