Features of the impact of the solar wind diamagnetic structure on Earth’s magnetosphere

Abstract

In Earth’s orbit on June 28, 1999, there was a diamagnetic structure (DS) representing a filament with a uniquely high speed (about 900 km/s). We show that the filament is a part of the specific sporadic solar wind (SW) stream, which is characterized as a small interplanetary transient. We report the results of studies on the interaction between such a fast filament (DS) and Earth’s magnetosphere. Around noon hours at daytime cusp latitudes, we recorded a powerful aurora in the UV band (shock aurora), which rapidly spread to the west and east. Ground-based observations of geomagnetic field variations, auroral absorption, and auroras on the midnight meridian have shown the development of a powerful substorm-like disturbance (SLD) (AE~1000 nT), whose origin is associated with the impact of the SW diamagnetic structure on the magnetosphere. The geostationary satellite GOES-8, which was in the midnight sector of the outer quasi-capture region during SLD, recorded variations of the Bz and Bx geomagnetic components corresponding to the dipolization process.

Keywords

• streamer
• filament
• diamagnetic structure; dayside auroras
• shock aurora
• substorm-like magnetospheric disturbance