Houston, TX 77005
12:00 p.m. Monday, Dec. 10, 2012
On Campus | Alumni
In this talk we demonstrate the oscillatory flow behavior observed by the five THEMIS probes in 2008-2009 seasons. Firstly, we use THEMIS observations of a single oscillatory flow event on 17 March 2008 between 10:22 and 10:36 UT to show that (i) the oscillatory flow is accompanied by interlaced enhancements and depletions of radial pressure gradients, and that the earthward and tailward flow bursts caused formation of vortices with opposite sense of rotation. (ii) We further study the ionospheric response (Pi2 pulsations) of the oscillatory flow by calculating different current components generated in the plasma sheet and correlating the space and ground observations. In addition we identify the auroral forms that are generated in the magnetically conjugated locations during the plasma sheet oscillatory flows. (iii) We investigate the mechanism of transient electron injection into the loss cone that may generate these auroral forms. We suggest that the electron injection into the loss cone may be due to scattering by the whistler waves and due to parallel acceleration of electrons captured by the stronger whistler waves. Secondly, using 25 observations of a damped oscillatory flow behavior in the near-Earth plasma sheet by the five THEMIS probes during 2008-2009 seasons, we derive the parameters of an oscillating thin filament, such as its oscillation period, and damping factor, and also the filament's entropy. We further use an empirical model to reconstruct the plasma parameters in the background plasma sheet. We find that the observed oscillation period of the filament would be in a satisfactory agreement with the one predicted by Wolf et al., 2012. The former fact suggests that the observed damped oscillatory flow behavior in the near- Earth plasma sheet may indeed be well explained by the theory of an oscillatory braking of a thin filament.