SPRG Seminars
March 9, 2010:
" Large-Scale Effects of Parallel Electric Fields "
Dr. Robert Ergun, LASP/CU Boulder
Both FAST and THEMIS satellites have made direct observations of parallel electric fields carried by double layers in the auroral zone and in the central plasma sheet of the Earth's magnetosphere. Double layers in the aurora have been observed in the upward current region, the downward current region, and in association with Alfvén waves. In the central plasma sheet, double layers are observed during bursty bulk flow events, in the current sheet, and plasma sheet boundary layer, all during periods of strong magnetic fluctuations. These observations imply that strongly nonlinear and kinetic behavior is intrinsic to the magnetic field lines that connect to the Earth's aurora. I discuss the possibility that parallel electric fields may be important in de-tangling magnetic field lines after reconnection and be responsible for subsequent rapidly progressing the turbulent cascade of Alfvén waves.