ALBERT

Beschreibung: The spatial and temporal features of the peak proton flux detected near the equator in the integral energy channel of 0.64-35MeV by S-1 telescope on board the EXOS-C mission were studied for a period of three years (1984-86). The equatorial zone (±30° geomagnetic latitude) proton data obtained for the angle between the telescope axis and the magnetic field direction in the range of 50°-130°and at the peak efficiency of the instrument, were sorted out from a study of the orientation of the telescope axis and calculation of the response function of the telescope. The data, after freed from the major influence of the South Atlantic Anomaly, and subsequently analyzed, revealed some new results contrary to the earlier observation (Moritz, 1972) in the altitude range of 350 to 850km. The spatial distribution shows that the global profile of the peak proton flux is aligned with the profile of the minimum magnetic field, and, the peak proton population straddles the minimum magnetic field equator with a full-width-at-half-maximum of about 19°. Also, the pitch angle distribution of the equatorial proton population is found to have the anisotropy index in the range 7 to 10. Further, the proton flux shows altitude, L, and longitude dependences. The flux increases as h1.43 and L4.25-7.50 (corresponding to different equatorial pitch angles). Besides, in the longitude range 180°〈Φ〈300°, the flux is significantly larger than that in the range 100°〈Φ〈180°. The fact of L independence of low energy (〈5MeV) protons, and the strong L dependence (L81) of high energy (〉5MeV) protons, has been used to infer the presence of a major low energy component and a minor high energy component. In the study of temporal features, comparison of absolute fluxes during two solar epochs shows that the proton flux during the solar minimum in 1984-86 was, at least, 40 times less than that during the solar maximum condition in 1982, possibly, due to lesser amount of hydrogen escape to the exosphere during the minimum condition, and thereby causing less precipitation of low energy particles in the equatorial atmosphere. © 1992, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.

Beschreibung: The instruments for the HEP (High Energy Particle) experiments of the Geotail mission, launched in July 1992, consist of 5 spectrometers (Ld, Bd, Mi-1, Mi-2 and Hi). The LD (Low energy particle Detector) and the Bd (Burst Detector) are mainly used to measure electrons, protons, helium and oxygen ions which reflect plasma dynamics in the magnetotail region. On the other hand, Mi-1, Mi-2 (Medium energy Isotope telescope-1, -2) and Hi (High energy Isotope telescope) are used to measure the isotope abundance of solar flare particles and cosmic ray particles which reflect physical conditions of interplanetary space and origin of these particles. In this paper, the objectives of these experiments, the details of the instruments and preliminary results from the observation in the magnetotail are given. The preliminary results obtained by the LD and BD show that a highly collimated beam of energetic particles appear in the plasma sheet just after the substorm onset and that directional distribution of particles can be radically different for different energies. In the Mi and HI telescopes, details a remarkable enhancement of anomalous cosmic ray components (N, O) in the quiet time of solar activity is reported, as well as the element composition of galactic cosmic rays. © 1994, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.

Beschreibung: Observations of fluxes and energy spectra of electrons (0.19–3.2 MeV) and protons (0.64–35 MeV) by OHZORA satellite are reported. The results obtained during March 14-June 22, 1984 are discussed in this paper. The maximum fluxes of electrons and protons are observed in the South Atlantic Anomaly and the auroral zones. Narrow peaks of counting rate in “the midlatitude zone” of L = 1.6 are observed over the south Pacific Ocean and Mexico, and the pitch angle distribution of the particles shows that these particles are geomagnetically trapped. Temporarily intensive proton and He ion fluxes at the north polar cap region are observed, and their particle energy spectrum shows that solar flare particles are injected into the polar cap. © 1985, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.