Whistler precursor and intrinsic variability of quasi-perpendicular shocks

Abstract

The structure of whistler precursor in a quasi-perpendicular shock is studied within two-fluid approach in one-dimensional case. The complete set of equations is reduced to the KdV equation, if no dissipation is included. With a phenomenological resistive dissipation the structure is described with the KdV-Burgers equation. The shock profile is intrinsically time dependent. For sufficiently strong dissipation, temporal evolution of a steepening profile results in generation of a stationary decaying whistler ahead of the shock front. With the decrease of the dissipation parameter whistler wavetrains begin to detach and propagate toward upstream and the ramp is weakly time dependent. In the weakly dissipative regime the shock front experiences reformation. †

How non-stationary are moderately supercritical shocks?

“…Here figure 1 is for illustrative purposes only. As a side note: the small-scale fluctuations in (b) resemble the waves generated by the ramp and propagating to both directions, as argued by Granit & Gedalin (2018). This is only a speculation at this stage though.…”