Journal Article

Electron distributions during the solar electron burst of 22 March 2002

Gosling, J. T., Steinberg, John T., de Koning, Curt A., Wang, Linghua, Lin, Robert P., Skoug, Ruth M.

2011

Overview

A compilation of various spacecraft measurements made over the last 30 years suggests that the pitch angle distribution (PAD) width of a solar electron burst may have a complex energy signature. To date, no study has considered the PAD width over a broad energy range during a single solar electron burst. Here we use Wind 3DP data to examine the energy dependence of the PAD width between 100 eV to 100 keV during the solar electron burst of 22 March 2002. We find that the PAD width during this event varied nonmonotonically with energy, with a minimum in the width‐energy profiles often being observed between 10 and 20 keV. In addition, we find time periods during and after the burst when the PAD width‐energy profile had a distinct maximum or protuberance below 10 keV. The times at which the protuberance appeared were coincident with Type III radio events. This suggests that the protuberance in the width‐energy profiles may be a manifestation of electron scattering by the electron/electron instability, as previously predicted by simulations. Key Points We use Wind 3DP data to examine the energy dependence of the PAD on 22 March 2002 We find a distinct maximum in the width‐energy profile below 10 keV The maximum may be a due to scattering by the e/e instability

• Publisher: Blackwell Publishing Ltd
• Subject: Astronomy / Astrophysics / electron/electron instability / energy dependence / pitch angle distribution / Plasma physics / solar electron bursts / Solar energy / Space / Spacecraft / Sun / Wind