Analysis of long decay periods observed from the HEO satellites in the vicinity of the slot region

Long decay periods of electron counts, that follow abrupt rises and last from weeks to months, have been measured by HEO3 in the vicinity of the slot region between the years 1998 and 2007. After selecting the most stable decay periods, i.e. lasting the longest, spread over L values ranging between 2.2 to 3.5, and stable for each one of the six HEO energy channels (between >100 keV to >3 MeV), e-folding timescales are extracted for every location and energy. These values will be compared to the timescales previously observed from SAMPEX during the same period [Meredith et al., 2007; Baker et al., 2007], to the first HEO ones extracted at L=3 [Fennell et al., 2012] and to the ones measured by CRRES [Meredith et al., 2006]. Another challenge is to be able to reproduce the observed timescales from simulations of pitch angle diffusion by the different acting waves of the plasmasphere, mostly plasmaspheric hiss, lightning-generated, and VLF transmitter waves. To do that, the recently developed analytical model of [Mourenas and Ripoll, 2012] is used to narrow the ranges of all wave amplitudes, as well as to locate the resonance domains associated with each of the different waves. Full numerical simulations are then performed, with the use of either the wave parameters from CRRES or the ones from [Abel & Thorne, 1998], to compute accurately the electron lifetimes. Similarities and differences between measurements and simulations will be discussed. We will also show how such understanding leads eventually to relate particular wave properties to the diffused electron energy and the implication it has on future analysis.