Magnetospheric boundary layers as seen by the Cluster spacecraft
Swedish Institute of Space Physics
This talk presents two studies based on data from ESA's four-spacecraft mission Cluster.
In the first example whistler-mode waves are observed in the boundary layer on the magnetospheric side of the magnetopause. The whistler waves are generated in small tube-like regions and the waves can be used as an instrument to investigate the structure of the boundary layer. The waves are believed to be a result of magnetic reconnection at the magnetopause. We suggest that each tube is linked to an electron diffusion region and that the large amount of tubes indicates patchy reconnection.
The topic of the second part of the talk is the dynamics in the turbulent magnetospheath. In this environment thin current sheets are formed, and RetinÃ² et al. (Nature Physics, 2007) found evidence that magnetic reconnection occurs in these layers. The width of a typical current sheet is of the order of an ion gyroradius but the reconnection signatures are the same as for large-scale reconnection at the magnetopause or in the solar wind. A statistical study of the current sheets in the magnetosheath is done in order to determine the probability that reconnection actually takes place given a thin current sheet in a this turbulent plasma. If reconnection turns out to be common in the magnetosheath, we expect it to be a common process in turbulent plasmas throughout the universe.
Created 2009-08-27 08:33:39 by Mats HolmstrÃ¶m Last changed 2009-09-15 23:44:18 by Mats HolmstrÃ¶m