M. Slivka

Energetic ions and electrons within the magnetosheath and upstream of the bow shock: Interball-1 overview

Abstract We present the results of a statistical survey of Interball-1 DOK-2 energetic ( E > 20 keV ) ion and electron observations in the solar wind and magnetosheath. Using four years of 2-min averages, we demonstrate the manner by which solar wind parameters control energetic particle fluxes within the foreshock. As the angle between the interplanetary magnetic field (IMF) and the normal to the bow shock decreases, ion flux increase and ion spectra soften. Ion spectra harden for higher solar wind velocities and greater geomagnetic activity. While ion fluxes generally decrease with distance from the magnetopause, the flux of ions also increases when the angle between the IMF and the normal to the bow shock decreases, particularly at low energies.

Energetic ions upstream of the Earth's bow shock: INTERBALL-1 survey

Abstract A statistical survey of energetic ions (> 20 keV) observed by the DOK2 experiment on Interball-1 during foreshock intervals from 1996 to 1998 is presented. Flux levels depend on the connection geometry, with higher values at quasi-parallel shocks, particularly at lower energies. The decrease of flux in diffusive events with distance from the bow shock is consistent with results from earlier surveys performed closer to the bow shock. The energy spectra are softer for quasi-parallel than quasi-perpendicular connections. The reflected ions have musch softer spectra. The cumulative frequencies for flux level occurrence patterns exhibit differences for quasi-parallel and quasi-perpendicular geometries up to approximately 200 keV.

Medium energy proton fluxes outside the magnetopause: INTERBALL-1 data

Abstract The extensive data set of the DOK2 energetic proton measurements indicates a decrease of flux at 22 – 29 keV based on the distance from the magnetopause within the magnetosheath. In the region upstream from the bow shock the signatures expected for the preferential acceleration of protons at quasiparallel shocks are found in the data. In addition to the proton leakage from the magnetosphere observed in several experiments, the observations confirm the importance of bow shock acceleration for the population of medium energy protons in the near upstream region.

High energy particle dispersion events observed by interball-1 and -2

Abstract Time period from October 1996 until January 1998 was checked on high energy resolution DOK2 energetic particle instrument measurements on Interball-1 and Interball-2 for the ion (> 20 keV) dispersive events (EDIS) with the exclusion of Interball-1 orbit parts in the tail. A variety of energy dispersive events, both in ion and electron spectra with different duration is found in the auroral regions, in the outer magnetosphere and near the cusp. While EDIS were observed in all sectors of MLT, the best conditions for their observation were in the afternoon local time. The characteristics of dispersive events observed by DOK2 are consistent with their explanation by the gradient-curvature drift of particles from the injection point(s) in the night local time sector given in Lutsenko at al., 2000a, b.

Medium energy particle perspective from magnetopause to upstream region: Prognoz-10 data

Abstract We present typical examplesof Prognoz-10 ion (E>15 keV) and electron (E> keV) flux observations as the spacecraft crosses the low and mid-latitude magnetosheath and the foreshock. Both leakage from magnetosphere and bow shock acceleration contribute to magnetosheath populations. A statistical survey using 6 months of measurements reveals that the occurence of high ion and electron fluxes depends upon K p . For the same K p , the probability of high ion occurence is much higher in the magnetosheath than in the upstream region. In the upstream region, the occurence of high ion fluxes depends upon the distance to the bow shock and on the angle Θ Bn .

Acceleration of electrons at the quasi-perpendicular bow shock according to intershock data

Abstract The structure of intense fluxes of energetic electrons ≳ 30 keV observed near the quasi-perpendicular bow shock is investigated. It is shown that electrons are accelerated only in the cases when the angle θ Bn between magnetic field lines and the normal to the shock surface is very close (± 2°) to 90°. This result is in a good agreement with the theory.

Energetic ions in the magnetosheath: Statistical study of spectra and anistropy

Abstract Prognoz-10 energetic ion measurements (E > 15 keV) in the magnetosheath (MSH) covered wide range of longitudes and low as well as medium latitudes. From all available 4 energy channel measurements of DOK-1 in MSH the energy spectra in 15–950 keV is shown to be harder close to magnetopause (MP) than deep in MSH. The streaming of ions dawnward and duskward close to MP is not showing any clear pattern in (zy) GSE plane. This is consistent with suggestion of patchy structure of merging at MP and leakage of magnetospheric particles to MSH.

Energetic proton spectra upstream of the bow shock from intershock project

Abstract Temporal profile and energy spectra of protons E p > 15 keV and flux of electrons E e > 30 keV in the dusk sector of upstream bow shock region are studied for series of particle events on 09.05.85 and 03.05.85 according to Prognoz-10-Intercosmos data. Relations of these parameters with magnetic field connection geometry and connection time are examined. Two different proton energy spectra are obtained.

PLASMA-F experiment: Three years of on-orbit operation

Composition and tasks of the PLAZMA-F experiment onboard the SPEKTR-R satellite are described in this paper. A record high time resolution is a feature of solar wind plasma flux and energetic particle flux measurements. It allowed detecting a number of new and significant properties and parameters.