Contribution of Yushmanov-trapped electrons to a thermal dike

A substantial amount of Yushmanov-trapped electrons are generated as a result of electron cyclotron resonance heating employed for generating a thermal dike in an open magnetic field configuration. The production rate and the energy spectrum of the trapped electrons are calculated by using a heating response function. The calculated energy spectrum of the end-loss electrons driven from the Yushmanov-trapped region indicates a reduction in power efficiency of the thermal dike. The potential profile modified by the Yushmanov-trapped particles tends to reduce their production rate, leading to a stationary state. Their significance to a thermal dike basic experiment in the end region of the GAMMA 10 tandem mirror [Plasma Physics and Controlled Nuclear Fusion Research 1992 (International Atomic Energy Agency, Vienna, 1993), Vol. 2, p. 651] is discussed. copyright 1996 American Institute of Physics