Daytime observations of energetic auroral-zone electrons

Abstract

Daytime electron precipitation has been observed from onboard Nike Apache sounding rockets launched from Fort Churchill, Manitoba, Canada. Energy spectra and pitch‐angle distributions are presented. Rapid time variations are seen at energies greater than 60 kev, and travel time arguments indicate that the precipitation cause acts within a few RE of the earth.

Anisotropic pitch angle distribution of ~100 keV microburst electrons in the loss cone: measurements from STSAT-1

“…This observation suggests that the pitch angle anisotropy increases for the higher energy electrons. Our observation is consistent with the results obtained by Lampton (1967) who observed anisotropic pitch angle distributions with rocket experiments. In the following section, we focus on how such microburst anisotropy occurs and how it is related with acceleration/loss processes of radiation belt electrons.…”

“…Microburst precipitation has been observed since the early sixties by balloon-borne X-ray experiments in the energy range of ∼20-100 keV (Anderson and Milton, 1964). Microbursts can be characterized by exponential energy spectra with e-folding energies E 0 ∼ 5-20 keV (Anderson et al, 1966;Lampton, 1967;Rosenberg et al, 1990;Reinard et al, 1997;Datta et al, 1997). To distinguish them from the relativistic microbursts, we call these low energy microbursts.…”

Field-aligned electron bursts at high latitudes observed by OGO 4

“…From the dispersion of arrival times f o r particles of different energies, or lack of it, the source location can be calculated, assuming that particles of all energies originated simultaneously (Evans, 1966;Bryant et al, 1967;Lampton, 1967). Source locations from within an earth radius to the tail region have been --I implied by the data.…”

Energy spectral characteristics of auroral electron microburst precipitation

“…Microbursts are predominately observed between dawn and dusk local time [Parks, 1978]. The temporal structures of microbursts include the symmetric form, the fast rise-slow decay form, and the slow rise-fast decay form [Anderson et al, 1966].…”

“…Neither of these locations has been verified. Until recently, only one rocket measurement of primary microburst electrons has been reported [Lampton, 1967] and that measurement included three broad energy channels (60-90 keV, 90-150 keV, 150-300 keV).…”