Paper#: 21
Poster #: 13
Session Name: Poster Session 2
Room: East Ballroom
Day: Thursday
Time: 10:10 a.m.-Noon
Abstract Title: Fast Bursts of High Energy Protons and Their Role in Triggering of the Substorm Onset Instability
PresentSurname: Korth, A.
All Authors: L. Lazutin, A.Korth, T. Kozelova
Abstract : The very first explosive instability of a substorm arises in restricted area, therefore satellites in geostationary region usually register one of the subsequent local activations timelagged to very first one in several minutes. At the same time, such local activations have all signatures of a main substorm onset, such as the dipolarization of a magnetic field and an increase (injection) of the energetic electron flux at the moment of the onset. Some minutes before that, tailward extension of magnetic field lines (accelerated growth phase) take place accompanied by an increase of a flux of energetic protons. This similarity or identity with the main onset instability allows us to use all local observations for the study of a fine structure of a substorm onsets. In the present report such analysis of a fine structure was made based on the measurements on the CRRES satellite. The main findings are related to the onset triggering agent. Several seconds prior to the onset (beginning of the dipolarization) we observed sharp increase of a flux of ions (protons) in range of energies restricted from lower energies at a 50-200 keV level, which possible is responsible for the triggering of onset instability. The absence of simultaneous increase of electrons and of a smaller energy protons suggests a resonant acceleration of trigger protons. It is shown, that during initial seconds only trapped proton flux is growing, that speaks that the acceleration took place at the equatorial region.