Propagation of nonlinear slow waves produced by pressure pulses along the Io flux tube

Abstract

A pressure enhancement in the vicinity of Io can be created in the course of the torus plasma flow around Io due to mass loading or it can be produced by volcanic outbursts on Io. For a given magnetic flux tube crossed by Io, a pressure pulse generates two slow magnetosonic waves propagating along the tube to the southern and northern ionosphere of Jupiter. These slow waves evolve rather quickly into shocks due to a steepening mechanism with accelerated plasma flow behind the shock front. This plasma flow streaming along the Io flux tube generates a field aligned potential difference, which can reach values of 1 kV for sufficiently strong pressure pulses. Therefore, this slow mode scenario seems to contribute to the Io controlled aurora as well as to the Io controlled Jovian decameter radiation (DAM) together with the generally accepted Alfvén wings model.