Electrostatic trapping of plasma electrons heated by whistler-wave electron cyclotron heating

Electron cyclotron heating (ECH) using whistler waves can lead to localized heating of plasma electrons, particularly in overdense plasmas. Quasineutrality is maintained by a positive ambipolar potential that electrostatically traps electrons and inhibits their escape from the resonant interaction region. In steady state the electron flux must equal that of the ions, which is at a speed comparable to the ion sound speed. The resulting equilibria are generally of the form of phase-space vortices whose spatial extent can be dictated by material walls or by atomic processes in the surrounding gas. In this paper the localization of electron heating is demonstrated and the nature of the resulting nonlinear, dynamic equilibria is discussed