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[en] Substantial evidence was accumulated over more than two decades that ion acceleration occurs at all collisionless shocks sampled directly in the solar system. The various shock waves in the heliosphere and the associated energetic particle phenomena are shown schematically. Three shocks have attracted considerable attention in recent years: corotating shocks due to the interaction of fast and slow solar wind streams during solar minimum, travelling interplanetary shocks due to coronal mass ejections, and planetary bow shocks. The signatures of these shocks and of their energetic particles are briefly reviewed. The most prominent theoretical models for shock acceleration are also reviewed. Recent observations at the earth's bow shock and at quasi-parallel interplanetary shocks are discussed in detail

[en] This paper reviews the properties of diffuse energetic ions observed at the quasi-parallel bow shock and at quasi-parallel interplanetary shocks. The first-order Fermi or diffusive acceleration mechanism can consistently explain the many detailed observational facts. In this model, it is assumed that particles are scattered approximately elastically in the solar wind frame, and gain energy by repeated scattering between the converging upstream and downstream flows or between the upstream flow and the shock. An essential feature at both the bow shock and at interplanetary shocks are self-excited low-frequency waves representing the scattering irregularities. The seed particles for the acceleration process at the bow shock are most probably solar wind ions. However, how and with what efficiency a certain fraction of the thermal solar wind population is injected into the acceleration process is at present only poorly understood. Whether the seed particles for the acceleration at interplanetary shocks are solar wind ions or more energetic ions is an open question. 73 references

[en] A 2D compressible MHD code is employed as an initial-value problem in the present simulations of reconnection in a doubly-periodic current sheet configuration, adding fluctuations to initial data in order to obtain reconnection. As previously shown by Matthaeus et al. (1986), islands grow in magnetic current sheets when either noise or turbulence is present. The kinetic energy production during the reconnection process appears to be independent of magnetic Reynolds number, while the enstrophy production increases with rising Reynolds number. 15 refs

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[en] The problem of cosmic-ray transport in supernova remnants (SNRs) is discussed under the assumption that wave-particle interaction is parasitic, i.e., the waves produced by the cosmic-ray streaming can be neglected. Calculations of the maximum ''active age'' of SNRs (i.e., the time during which the initially excited wave activity dies down) show that appreciable post-acceleration of cosmic rays may be possible, which in turn may lead to a replenishment of low-energy cosmic rays that otherwise are lost through ionization of the interstellar medium. Transport coefficients in coordinate and energy space are calculated in a realistic SNR model using the most plausible assumptions about wave activity and wave-particle interaction. This allows a quantitative determination of energy losses and gains to be made as a function of cosmic-ray rigidity

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[en] The ionic mass and charge composition of the suprathermal (10-230 keV/e) population of the plasma sheet has been measured using the Suprathermal Energy Ionic Charge Analyzer (SULEICA) on AMPTE/IRM before and after a substorm onset on April 8, 1985. Simultaneously with the substorm onset and strong earthward plasma flows, a flux increase of the suprathermal ions and a significant hardening of the spectra are observed that are most pronounced for O(+). The enhancement ratios can be best organized in terms of energy per charge. The observations are interpreted as an indication of particle acceleration by electric fields and additional injection of ionospheric plasma into the plasma sheet after substorm onset. 12 references

[en] Observations of energetic particle fluxes in the geomagnetic tail show that these particles exhibit a bursty appearance on all time scales. Often, however, the bursty appearance is merely due to multiple entries and exits of the spacecraft into and out of the plasma sheet which always contains varying fluxes of energetic particles. Observations of the suprathermal and high-energy component of the plasma sheet are discussed, and observations are presented of energetic particle bursts in the plasma sheet proper, which may be due to a locally ongoing acceleration process. Also discussed are energetic particle phenomena occurring near the edge of the plasma sheet, either during thinning or during recovery. Some recent results from the ISEE 3 deep tail mission bearing on energetic particle acceleration are presented, and the present status of the theory of particle acceleration within the magnetotail is briefly reviewed. 40 references