Particle acceleration in the magnetotail associated with magnetospheric substorms and storms

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1. We discuss the radial evolution of the fast flow in the tail associated with substorm based on statistical studies using GEOTAIL magnetic field and plasma data. While the tailward flow has a systematic tailward and spatial evolution, where a typical timescale 20-30 minutes can be identified, the earthward flow is differs from event to event.2. Changes in the structure of the distant tail associated with geomagnetic storms are studied by using plasma and magnetic field data obtained from GEOTAIL.Thirteen storm intervals between October 1993 and October 1994 are examined when the satellite was located in the distant tail between X=-83R_Eand*=-210R_E. GEOTAIL observed the magnetosheath during all storms including those when the satellite was located near the nomianl tail axis. It is found that an average energy of -5x 10^<15>J is stored also in the distant tail during the storm main phase, which is a comparable value to that stored in the midtail during an intense substorm growth phase reported in the previous studies.3. We studied flux variations in the outer radiation belt electrons during main phase and early recovery phase of geomagnetic storm using data obtained by SAMPEX.We examined 25 well defined storms with different activity level. By comparing with a simple model of ring current magnetic field perturbations, it is shown that the decrease is attributed to the adiabatic deceleration in response to the storm time magnetic field due to ring current particle. Such adiabatic response in most clearly detected between L=4-5, at the center of the 1 MeV radiation belt, and where the magnetic perturbation due to the ring current could have largest effect.