Charged Particle Behaviour during the Active Phase of the APEX Experiment.

Abstract

The Active Plasma Experiment (APEX) uses intensive electron beam emission for the study of dynamic processes in the magnetosphere and upper ionosphere. The beam energy and current is as high as 8 keV and 100 mA and the pitch angle of the emission varies in the range from 50° to 80°. The basic cycle of electron injection is formed by current pulses of different duration, intensity and frequency. The spacecraft potential is balanced by a low energy xenon plasma generator during the electron beam injection.The response of the environment is studied by the PEAS charged particle spectrometer working in the energy range 0.1-25 keV. The common response to the beam emission is the increase of the intensity of the registered electrons with energy less than 2 keV. Under some circumstances (the satellite position, the injector regime, the beam direction with respect to the magnetic field etc.), strong electron fluxes of the order of 107 cm 2sec IkeV-1 have been observed. The energy of these fluxes is in general a rising function of the mean current ofthe emitted beam but never exceeds the beam energy. The energy-angular distribution exhibits a complicated structure with the maximum energy located at the pitch angle which corresponds to that of the emitted electron beam.

Overview of APEX Project Results

“…Ion density N i , temperature T ix , T iz (planar retarding potential analyzers), ion drift in the YZ plane, and (Dokukin, 1992 electron temperatures T ex , T ey , T ez (planar probes with RF bias) were the output parameters of this instrument. The PEAS hot plasma spectrometer (Nemecek et al, 1993(Nemecek et al, , 1997 measured energy-angular distributions in two planes (2 double toroidal analyzers, 12 angular sectors each, electron/positive ion sweeps alternated). Its default operational mode provided one 16-energy level spectrum (50 eV-22 keV) of electrons and ions in 2.6 s (STO-AP), the sampling was not synchronized with the UEM-2/UPM data sampling.…”

“…3.4.1. Energetic Particles Nemecek et al (1996) and Prech et al (2002) reported on observations of short intensive bursts of narrow-beam electrons onboard MAGION-3 during the electron injections from the main IK-25 satellite. The events were registered in the middle geomagnetic latitudes (INL < 55 • ) near local noon when the two satellites moved approximately along the same magnetic meridian at relative distances 64-550 km.…”