Influence of Hot Plasma Pressure on the Global Structure of Saturn's Magnetodisk

TL;DR

This study models how variations in hot plasma pressure influence Saturn's magnetodisk structure, affecting magnetopause location and magnetic mapping, with validation against Cassini data showing reasonable agreement over long timescales.

Contribution

It introduces a force balance model linking hot plasma pressure variations to changes in Saturn's magnetic field configuration and validates predictions with observational data.

Findings

Hot plasma pressure variations alter the magnetopause position.

Magnetic mapping between ionosphere and disk is affected.

Model predictions agree with Cassini observations over long timescales.

Abstract

Using a model of force balance in Saturn's disk-like magnetosphere, we show that variations in hot plasma pressure can change the magnetic field configuration. This effect changes (i) the location of the magnetopause, even at fixed solar wind dynamic pressure, and (ii) the magnetic mapping between ionosphere and disk. The model uses equatorial observations as a boundary condition-we test its predictions over a wide latitude range by comparison with a Cassini high-inclination orbit of magnetic field and hot plasma pressure data. We find reasonable agreement over time scales larger than the period of Saturn kilometric radiation (also known as the camshaft period).