Quasilinear evolution of current-driven ion-acoustic instability in a magnetic field

Three-dimensional evolution of current-driven ion-acoustic instability in a magnetic field is studied numerically in the quasilinear framework. The electron-cyclotron resonance (anomalous Doppler effect) is shown to be responsible for the observed rapid cross-field heating of electrons. The formation of a high-energy ion tail, previously studied in a one-dimensional model, remains effective both parallel and perpendicular to the electron current and governs the saturation of the instability, subsequent decay, and anomalous k spectrum dominated by cross-field modes