Electron bounce resonance heating in a bumpy cylinder

In bumpy cylinder geometry, the electrons are classified into trapped and passing particles. The interaction between a wave near the electron bounce frequency and the electrons is studied both numerically and analytically for the appropriate parameters of ELMO Bumpy Torus-Scale (EBT-S). It is shown that coupling of the waves to the electron bounce motion parallel to the magnetic field can lead to heating of those electrons near the passing/trapped boundary in velocity space. The stochastic threshold condition is eE0k0/mω/sub b/2 approx. = 0.1. For this mechanism, it is found that the wave energy density required to induce stochastic heating in EBT by rf [in the frequency range of ion cyclotron resonance heating (ICRH)] is about an order of magnitude more than that estimated on the basis of cold plasma wave theory. It is hypothesized that this discrepancy would disappear when the thermal correction to the wave propagation and the effects of collisions and toroidicity are included. We also suggest that the bounce resonance can enhance the electron cyclotron resonance heating (ECRH) efficiency in an EBT-like heating scheme