Multi-point observations of the inner boundary of the plasma sheet during geomagnetic disturbances

[1] We report on the THEMIS and Double Star TC-1 observations at the geocentric distances of 3 < R < 8 RE during substorms on March 23, 2007. THEMIS crossed the inner boundary of the equatorial dusk-side plasma in the string-of-pearls configuration, allowing the dynamics of particle populations to be traced within time ranges from hours to 10 minutes. Observations show co-existence of the plasma sheet ion population (5-30 keV) with the ring current ion population (100-1000 keV) at 4 < R < 6 RE. The plasma sheet population was characterized by pronounced "nose''- like dispersion with the spectral density maximum at similar to 10 keV. The plasma sheet boundary, defined by a sharp decrease of the similar to 1 keV electron flux, moved inward to R = 4 and outward back to similar to 8 RE within about 1 hour. Local enhancements of the plasma sheet (1-5 keV) electron flux with the characteristic time scale of 2-10 min were detected at 5 < R < 6 RE during the substorm. Citation: Runov, A., V. Angelopoulos, N. Ganushkina, R. Nakamura, J. McFadden, D. Larson, I. Dandouras, K.- H. Glassmeier, and C. Carr (2008), Multi- point observations of the inner boundary of the plasma sheet during geomagnetic disturbances.