Radial transport and plasma heating in Jupiter's magnetodisc

TL;DR

This paper investigates plasma heating in Jupiter's magnetodisc, proposing an advection-based turbulence model supported by Galileo data, which better explains observed ion temperature increases than previous flux tube diffusion models.

Contribution

It introduces an alternative turbulent heating model based on advection, supported by spectral analysis of Galileo data, challenging previous flux tube diffusion explanations.

Findings

Observed turbulence could provide necessary plasma heating.

Advection model better explains ion temperature increase.

Supports shift from diffusion to advection in radial transport understanding.

Abstract

The ion temperature of the magnetosphere of Jupiter derived from Galileo PLS data was observed to increase by about an order of magnitude from 10 to 40 Jupiter radii. This suggests the presence of heating sources that counteract the adiabatic cooling effect of expanding plasma. There have been different attempts of explaining this phenomena, including a magnetohydrodynamic (MHD) turbulent heating model which is based on flux tube diffusion [Saur, Astrophys. J. Lett., 602, L137, 2004]. We explore an alternate turbulent heating model based on advection, similar to models commonly used in solar wind heating. Based on spectral analysis of Galileo magnetometer (MAG) data, we find that observed MHD turbulence could potentially provide the required heating to explain some of the increase in plasma temperature. This indicates that advection is a more appropriate way to describe radial transport of plasma in the jovian magnetosphere beyond 10 Jupiter radii.