Engineering topics
Publications and source records attributed to Sugiura, M..
Fluxgate magnetometer data obtained by OGO-5 near perigee were used to establish the existence of large field depressions in the magnetosphere under conditions of varying degree of disturbance at distances ranging from 2.3 to 3.6 R sub E at all local times. The results also provide the average delta B at these distances when Dst, as being derived at present, is zero.
The delta B distribution deduced from the Ogo 3 and 5 satellites shows large field depressions in the equatorial region inside the plasmasphere. On the basis of the delta B distribution, it is shown that what is usually considered the quiet-time ring current is an equatorial sheet current that is an extension of the neutral sheet current in the magnetospheric tail. The primary source of the large field reductions inside the plasmasphere is a population of protons with energies of 0.1-1 Mev initially detected by Davis and Williamson (1963) and Davis (1965) on Explorer 12, 14, and 15. Low-energy protons extensively measured on Ogo 3 by Frank (1967, 1971) are primarily responsible for the current near and outside the plasmapause.
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Provisional hourly values of equatorial atmospheric radiation conditions for the period January to June 1972 were obtained. The data are presented in numerical tables with graphical presentation of the digital data included.
Tables and plots of provisional hourly values of the equatorial Dst index for 1971 are given, a table of daily mean Dst values for 1971 is also provided. The base line values for the four observatories, Hermanus, Kakioka, Honolulu, and San Juan, were obtained from extrapolations using the coefficients for the secular variations determined for the previous years. Examining the Dst values for quiet days, the base lines so determined appear to be slightly low, so that the Dst index for quiet periods tends to be high.
Observations of the quiet time ring current intensity and distribution in the magnetosphere by OGO-3 and OGO-5 are given. The differences in quiet time ring currents and ring currents observed during magnetic storms are discussed.
It is proposed that the quiet-time ring current consists of two parts, the inner ring current imbedded deeply inside the plasmapause and the outer ring current flowing in the plasma sheet. The source of the inner ring current appears to be trapped protons with energies 100 keV to several hundred keV having their peak intensity at 3 to 4 R sub e. The dominant source of the outer ring current is the population of protons with energy near 50 keV in the plasma sheet, as in Frank's (1967) model for the extraterrestrial ring current. The outer ring current is an innermost part of the tail current, and the inner ring current is its earthward extension. The plasma pressure is nearly continuous from the plasma sheet to the inner current ring region. When the plasma sheet moves inward during a substorm, the plasma pressure increase is directly conveyed to inside the plasmasphere and intensifies the inner ring current.
The topology of delta-B (i.e., the observed scalar magnetic field intensity minus a scalar reference field intensity) in the magnetosphere has been established by the Rb magnetometer observations on OGO's 3 and 5. This delta-B topology provides a convenient framework, on the basis of which the complex features found by the earlier magnetic field observations made by Explorers 10, 12, 14, 26 and Electron 2 can be reinterpreted to fit a unified simple picture of the magnetospheric field distortions including the inflation of the equatorial magnetosphere by the ring current. It is proposed that the quiet-time ring current consists of two parts, the inner ring current imbedded deeply inside the plasmapause and the outer ring current flowing in the plasma sheet.
Description of studies of electrons between 10 eV and 9.9 keV in the solar wind. The transport of energy in the rest frame of the plasma is evaluated and shown to be parallel to the interplanetary magnetic field. The presence of electrons from solar events causes this energy-flux density to exceed the heat flow due to thermal electrons. In one such event, the observations are shown to be consistent with the solar-electron observations made at higher energies. When observations are made at a point connected to the earth's bow shock by an interplanetary-field line, a comparatively large energy flux along the field toward the sun is observed, but the heat flow remains outwardly directed during this time interval. In either situation the heat flow is found to be consistent with measurements made on Vela satellites by a different method. These values, less than .01 ergs/sq cm/sec, are sufficiently low to require modifications to the Spitzer-Harm conductivity formula for use in solar-wind theories.
The rubidium vapor magnetometer data of the scalar magnetic-field intensity obtained by the OGO 3 and 5 satellites are analyzed to study the magnetospheric-field distortions in terms of the observed field magnitude under quiet and slightly disturbed conditions minus the magnitude of the reference geomagnetic field (delta B). Average contours of equal delta Bs are shown in the geomagnetic noon-midnight and dawn-dusk meridian planes for magnetically quiet and slightly disturbed conditions. The equatorial distribution of observed delta Bs as a function of geocentric distance differs substantially from that expected from the well-known models of the quiet-time ring current. Other findings suggest that there must be a population of low-energy particles with substantial total energy near the equator at distances of 2 to 5 earth radii that has not been recognized as having sufficient energy to inflate the magnetic field.
Electron energy flux in solar wind, in energy range 25 eV to 9.9 keV
Beta particle observations between inner edge of plasma sheet to plasmapause in midnight earth magnetosphere
Hourly equatorial magnetic variations data for 1957 to 1970
Resonant oscillations of geomagnetic field in magnetosphere caused by solar wind
Magnetic field and electron plasma observations near dawn magnetopause by triaxial spectrometer and fluxgate magnetometer on satellite OGO 5
Magnetospheric field distortions observed from rubidium magnetometer measurements on OGO 3 and 5
Provisional hourly values of equatorial Dst for 1968
Magnetopause crossing observation of ATS 5 satellite during magnetic storm