Effect of a magnetosphere compression on Jovian radio emissions: in situ case study using Juno data

TL;DR

This study analyzes how Jupiter's magnetospheric compressions, inferred from Juno data, influence the activation and behavior of various Jovian radio emissions, revealing temporal and spatial emission patterns related to magnetospheric dynamics.

Contribution

It provides a detailed in situ analysis of Jovian radio emissions during magnetospheric compressions, linking solar wind pressure to radio source activation and dynamics.

Findings

Broadband kilometric emissions activate during compression

Decametric emissions activate after one rotation at specific longitudes

Narrowband kilometric radiation activates during expansion phases

Abstract

During its 53-day polar orbit around Jupiter, Juno often crosses the boundaries of the Jovian magnetosphere (namely the magnetopause and bow shock). From the boundary locations, the upstream solar wind dynamic pressure can be inferred, which in turn illustrates the state of compression or relaxation of the system. The aim of this study is to examine Jovian radio emissions during magnetospheric compressions, in order to determine the relationship between the solar wind and Jovian radio emissions. In this paper, we give a complete list of bow shock and magnetopause crossings (from June 2016 to August 2022), along with some extra informations (e.g. solar wind dynamic pressure and position of the standoff distances inferred from Joy et al. (2002)). We then select two compression events that occur in succession (inferred from magnetopause crossings) and we present a case study of the response of the Jovian radio emissions. We demonstrate that magnetospheric compressions lead to the activation of new radio sources. Newly activated broadband kilometric emissions are observed almost simultaneously to compression of the magnetosphere, with sources covering a large range of longitudes. Decametric emission sources are seen to be activated more than one rotation later only at specific longitudes and dusk local times. Finally, the activation of narrowband kilometric radiation is not observed during the compression phase, but when the magnetosphere is in its expansion phase.