Articles | Volume 35, issue 4
ANGEO Communicates
31 Jul 2017
ANGEO Communicates |  | 31 Jul 2017

Bursty emission of whistler waves in association with plasmoid collision

Keizo Fujimoto

Abstract. A new mechanism to generate whistler waves in the course of collisionless magnetic reconnection is proposed. It is found that intense whistler emissions occur in association with plasmoid collisions. The key processes are strong perpendicular heating of the electrons through a secondary magnetic reconnection during plasmoid collision and the subsequent compression of the ambient magnetic field, leading to whistler instability due to the electron temperature anisotropy. The emissions have a bursty nature, completing in a short time within the ion timescales, as has often been observed in the Earth's magnetosphere. The whistler waves can accelerate the electrons in the parallel direction, contributing to the generation of high-energy electrons. The present study suggests that the bursty emission of whistler waves could be an indicator of plasmoid collisions and the associated particle energization during collisionless magnetic reconnection.

Short summary
A large energy release can occur in association with magnetic field line reconnection. In order to understand the detailed process of the energy release, accurate satellite observations are invaluable. However, it is usually difficult to identify where a single satellite is located with respect to the reconnection process. The present study proposes using a whistler burst to identify the plasmoid collisions and associated electron acceleration in the reconnection process.