Dusk Side ULF Waves and Plasmaspheric Plumes
Abstract
Previous studies have shown frequent occurrence of compressional ULF waves with frequencies in the PC 5 range in the dusk side of the magnetosphere, from a distance of about 8 RE up to the magnetopause. These waves propagate sunward and towards the magnetopause with very low speeds in the plasma frame. Plasmaspheric plumes, extensions from the plasmasphere filled with relative cold plasma, are also a common presence in this region of the magnetosphere. Moreover, both phenomena appear preferentially after a weak increase in the geomagnetic activity. Here we discuss the relationship between the dusk side ULF waves and the plasmaspheric plumes. The ULF waves are identified and analyzed using magnetic field data from the FGM instrument onboard THEMIS. To identify the plasmaspheric plumes we use the spacecraft potential as a proxy for the particle density. Many events during April 2008 indicate a close relationship between ULF waves and plasmaspheric plumes. The waves are often detected between the plume and the magnetopause, but sometimes also within the plumes.
- Publication:
-
38th COSPAR Scientific Assembly
- Pub Date:
- 2010
- Bibcode:
- 2010cosp...38.2207D