Coupling between whistler waves and slow-mode solitary waves

TL;DR

This paper investigates how whistler waves can be linearly coupled and trapped within slow magnetosonic solitons in plasma, using two-fluid simulations to explore their interaction in inhomogeneous conditions.

Contribution

It presents the first numerical study demonstrating the trapping and transport of whistler waves inside slow magnetosonic solitons in plasma.

Findings

Whistler waves can be trapped in density inhomogeneities.

Whistler waves are transported inside slow magnetosonic solitons.

The study links ion-scale structures to electron-scale wave phenomena.

Abstract

The interplay between electron-scale and ion-scale phenomena is of general interest for both laboratory and space plasma physics. In this paper we investigate the linear coupling between whistler waves and slow magnetosonic solitons through two-fluid numerical simulations. Whistler waves can be trapped in the presence of inhomogeneous external fields such as a density hump or hole where they can propagate for times much longer than their characteristic time scale, as shown by laboratory experiments and space measurements. Space measurements have detected whistler waves also in correspondence to magnetic holes, i.e., to density humps with magnetic field minima extending on ion-scales. This raises the interesting question of how ion-scale structures can couple to whistler waves. Slow magnetosonic solitons share some of the main features of a magnetic hole. Using the ducting properties of an inhomogeneous plasma as a guide, we present a numerical study of whistler waves that are trapped and transported inside propagating slow magnetosonic solitons.