The University of Arizona

Resistive Heating in Saturn's Upper Atmosphere...and the Difficulties in Calculating It

Resistive Heating in Saturn's Upper Atmosphere...and the Difficulties in Calculating It

Series: Program in Applied Mathematics Brown Bag Seminar
Location: Math 402
Presenter: Jess Vriesema, Lunar and Planetary Laboratory, University of Arizona

The upper atmospheres of all gas giant planets in our solar system are several times hotter than solar heating alone can account for. This implies a yet-unidentified heating source, which has eluded scientists for decades. Among other suggested heat sources, wind-driven resistive heating (AKA "Joule heating" or "Ohmic dissipation") is an attractive candidate to study because it is a direct, in-situ heat source and is expected to be significant on at least Saturn. In this model, ionized winds moving past a background magnetic field can induce charge separation and cause currents to flow in the ionosphere and thermosphere, which then cause resistive heating. My approach is to calculate the electric field produced by the ionospheric dynamo implicitly using finite differences to solve the 2D PDE. My difficulty is that the problem is poorly scaled and boundary conditions are somewhat unclear (or possibly inconsistent?) for all but the most simplified scenarios.

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