Enhancement of Terrestrial Diffuse X-ray Emission Associated With Coronal Mass Ejection and Geomagnetic Storm

TL;DR

This study analyzes Suzaku observations during a 2005 geomagnetic storm, revealing how solar wind interactions and atmospheric heating enhance diffuse X-ray emissions, with implications for space weather effects.

Contribution

It demonstrates the correlation between solar wind flux and X-ray emission lines, and estimates the ion entry into the magnetosphere during a storm.

Findings

Time variation in diffuse X-ray emission during geomagnetic storm.

Correlation between solar wind flux and O VII line flux.

Evidence of solar wind ions entering the magnetosphere.

Abstract

We present an analysis of a Suzaku observation taken during the geomagnetic storm of 2005 August 23-24. We found time variation of diffuse soft X-ray emission when a coronal mass ejection hit Earth and caused a geomagnetic storm. The diffuse emission consists of fluorescent scattering of solar X-rays and exospheric solarwind charge exchange. The former is characterized by a neutral oxygen emission line due to strong heating of the upper atmosphere during the storm time, while the latter is dominated by a sum of C V, C VI, N VI, N VII, O VII, and O VIII emission lines due to the enhanced solar wind flux in the vicinity of the exosphere. Using the solar wind data taken with the ACE and WIND satellites,a time correlation between the solar wind and the strong O VII line flux were investigated. We estimated necessary column densities for the solar X-ray scattering and exospheric SWCX. From these results, we argue that a part of the solar wind ions enter inside the magnetosphere and cause the SWCX reaction.