Electron dynamics and whistler waves at quasi‐perpendicular shocks

Abstract

The collisionless, supercritical, quasi‐perpendicular fast shock is investigated on sub‐ion scales using an implicit, two‐dimensional (2‐D) full particle code. For the first time, simulations are carried out with realistic characteristic frequencies and sufficiently high mass ratio between the protons and electrons. As a result, there is relatively little scattering of the electrons, i.e., they behave largely adiabatically as previously suggested based on spacecraft observations at the Earth's bow shock. The large mass ratio also allows for a realistic description of the whistler mode dispersion. Phase‐standing whistlers with propagation along the shock normal appear as transients. The dominant whistlers found at late times in the simulations have upstream directed group velocity but propagate at oblique direction between the shock normal and the ambient magnetic field. Their properties match those of the ubiquitous observed upstream whistlers (“one‐Hertz waves”).