RING CURRENT ION FLOWS AND CONVECTION ELECTRIC-FIELD AS EXPECTED FROMOBSERVATIONS BY SAC-B ISENA/

In the present paper, ENA energy spectra at the location at the SAC-B satellite are simulated by using AMPTE/CCE/CHEM ion distributions as o riginating source, with the purpose of analysing the SAC-B/ISENA respo nse at different magnetic local times and latitudes. The shape of the ENA spectra simulated along different lines of sight on the equatorial plane is analysed to show that an instantaneous estimate of the globa l convection electric field will be possible with the ISENA data every few minutes. This unprecedented time resolution for the measurement o f such a crucial parameter of the Earths magnetosphere will allow test ing of many theories, like tail convection, pressure balance, global c ircuits, ring-current shielding, etc.