Statistical Study on the Sources of Jovian Decametric Radio Emissions Based on the Radio Observations of Remote Instruments

TL;DR

This study statistically analyzes Jovian decametric radio emissions using multi-spacecraft observations, revealing source locations, emission angles, and electron energies, and highlighting asymmetries in Jupiter's magnetic field influence.

Contribution

It introduces a comprehensive statistical approach to locate DAM sources and infer their characteristics based on multi-view observations, advancing understanding of Jovian radio emissions.

Findings

DAM sources cluster in three preferred regions influenced by magnetic field asymmetry.

Io-related DAMs have rotation speeds between 0.15-0.6Ω_J, non-Io-DAMs between 0.7-1.2Ω_J.

Emission angles range from 60° to 85°, with electron energies mainly between 0.5 and 20 keV.

Abstract

To better understand the physical processes associated with Jovian decametric (DAM) radio emissions, we present the statistical study of DAMs and inferred characteristics of DAM sources based on multi-view observation from Wind and STEREO spacecraft. The distribution of the apparent rotation speed of DAMs derived from multiple spacecraft suggests that the rotation speed of Io-related DAMs is in range of 0.15-0.6{\Omega}_J and that of non-Io-DAMs is between 0.7-1.2{\Omega}_J. Based on the method of Wang et al. (2020), we locate the sources of the DAMs and infer their emission angles and associated electron energies. The statistical results show that the DAM source locations have three preferred regions, two in the southern hemisphere and one in the northern hemisphere, which is probably caused by the non-symmetrical topology of Jupiter's magnetic field. The difference between Io-DAM source footprints and Io auroral spots changes with the Io's position in longitude, consistent with the previous results from Hess et al. (2010), Bonfond et al. (2017) and Hinton et al. (2019). In addition, the emission angles for non-Io-DAMs are smaller than that for Io-DAMs from the same source regions and all the emission angles range from 60{\deg} to 85{\deg}. Correspondingly, the electron energy is mainly distributed between 0.5 and 20 keV.