Signatures of particle precipitations at European middle latitudes during the March 2015 magnetic storm

Abstract

Large geomagnetic storms can trigger an extension of auroral ionosphere to middle latitude. We present a study of fine-scale ionospheric disturbances in northern Germany during the March 2015 magnetic storm based on satellite and ground radar monuments. Localized electron density enhancements on the scale of several Total Electron Content Unit [TECU] over the horizontal distance of < 50 km are observed to be generated by ionization due to precipitating particles. We discuss that plasma instabilities triggered by these fine-scale particle precipitations under large electric fields can explain the forcing effects of the previously reported unusual E-region irregularities during this storm. Our study demonstrates that regional ionospheric disturbances at middle latitudes during the March 2015 storm occurred on much smaller spatial scales than previously studie