Electron-cylotron maser radiation from electron holes: Downward current region

TL;DR

This paper proposes that electron-cyclotron maser radiation from electron holes in the downward current region contributes to the fine structure of auroral kilometric radiation, complementing the main emission from the upward current region.

Contribution

It introduces a model linking electron holes in the downward current region to fine structures in auroral kilometric radiation, expanding understanding of emission sources.

Findings

Electron holes in the downward current region generate fine structure in auroral kilometric radiation.

Main background radiation originates from the upward current region's electron ring distribution.

Both regions contribute to auroral kilometric radiation via the same maser mechanism.

Abstract

The electron-cyclotron maser emission from electron holes is applied to holes generated in the downstream current region of the aurora. We suggest that part of the fine structure observed in the auroral kilometric radiation is generated by the electron-cyclotron maser mechanism in the downstream current region. The argument goes that the main background auroral kilometric radiation source is still located in the partial electron ring (horseshoe) distribution of the upward current region while the fine structure is caused by electron holes generated predominantly in the downward current region. Since both regions always exist simultaneously they are acting in tandem in generating auroral kilometric radiation by the same mechanism though in different ways.