Magnetosphere-Ionosphere Coupling Through E-region Turbulence 1: Energy Budget

TL;DR

This paper investigates the energy transfer processes in the Earth's ionosphere during geomagnetic activity, focusing on plasma turbulence, anomalous electron heating, and their effects on ionospheric conductance, using a theoretical two-fluid model.

Contribution

It provides a first-principles proof that the energy source for plasma turbulence and heating is the work done by external electric fields on non-linear currents.

Findings

Proves the energy source for turbulence equals external work on non-linear currents.

Describes energy conversion using a two-fluid plasma model.

Reconciles 2-D non-linear currents with 3-D anomalous heating.

Abstract

During periods of intense geomagnetic activity, strong electric fields and currents penetrate from the magnetosphere into high-latitude ionosphere where they dissipate energy, form electrojets, and excite plasma instabilities in the E-region ionosphere. These instabilities give rise to plasma turbulence which induces non-linear currents and strong anomalous electron heating (AEH) as observed by radars. These two effects can increase the global ionospheric conductances. This paper analyzes the energy budget in the electrojet, while the companion paper applies this analysis to develop a model of anomalous conductivity and frictional heating useful in large-scale simulations and models of the geospace environment. Employing first principles, this paper proves for the general case an earlier conjecture that the source of energy for plasma turbulence and anomalous heating equals the work by external field on the non-linear current. Using a two-fluid model of an arbitrarily magnetized plasma and the quasilinear approximation, this paper describes the energy conversion process, calculates the partial sources of anomalous heating, and reconciles the apparent contradiction between the inherently 2-D non-linear current and the 3-D nature of AEH.