Spatial distribution of auroral precipitation during storms caused by magnetic clouds

The global pattern of auroral precipitation and dynamics of precipitation boundaries during three different intensity magnetic storms driven by magnetic clouds were investigated. For the aim of the research, the empirical model (http://pgia.ru/lang/en/webapps/) in which the boundary locations of the auroral precipitation depend on the geomagnetic activity expressed by the AL- and Dst indices was used. The locations of the boundaries derived from DMSP F10–F15 spacecraft observations were compared to those obtained in the model and displayed reasonable agreement. We find a significant displacement to the lower latitudes of the diffuse auroral zone (DAZ) and auroral oval precipitation (AOP) region with the increase of magnetic activity. The planetary pattern of auroral precipitation indicated different dawn–dusk widening of the DAZ and AOP region (asymmetry) during both main and recovery phases of magnetic storms. Differences in the dawn–dusk widening (i.e., asymmetry) of the DAZ and AOP zone during magnetic storms appear to be sensitive to Dst, where the DAZ widens in the morning only, while the AOP widens in the evening under all Dst intensities, and widens significantly in the morning also for Dst<−100 nT. The average energy of precipitating electrons in both MLT sectors and both zones was estimated and compared with DMSP spacecraft data.

► The global pattern of auroral precipitation during magnetic storms was investigated. ► The empirical model (http://pgia-webapps-www/apm/) was used. ► Different dawn–dusk widenings of DAZ and AOP region during the phases of the storm are shown. ► A change in the width of the DAZ and AOP region (asymmetry) mostly depends on the storm intensity. ► The average electron energy in the morning and evening MLT-sectors during the storms is estimated.