Explorer 10 plasma measurements

Abstract

Plasma measurements were made with a detector aboard the Explorer 10 satellite, launched on a highly elongated elliptical trajectory with the line of apsides about 33° to the antisolar direction. Magnetic field measurements were also carried out on Explorer 10 by the Goddard Space Flight Center of NASA. A plasma moving with a velocity of about 300 km sec−1 was first observed when the satellite reached a distance of about 22 earth radii. During the rest of the observations (which terminated about 40 hours later, at a distance of 42 earth radius, periods in which substantial plasma fluxes were recorded alternated with shorter periods in which the plasma flux was below or just above the detection limit. There was a striking correlation between the plasma flux and the magnetic field: in the absence of plasma the magnetic field direction was nearly radial from the earth, whereas in the presence of plasma, the field was irregular and generally formed large angles with the earth‐satellite direction. The plasma probe did not provide accurate information on the direction of the plasma flow, but placed the direction within a ‘window’ of about 20° by 80°. This window includes the direction pointing radially away from the sun. The flux densities of the positive ions (presumably protons) corresponding to the observed currents were of the order of a few times 108 cm−2 sec−1. They fluctuated over a range of about a factor of 2 during the periods when plasma was observed.

Solar Weather Event Modelling and Prediction

“…The existence of a supersonic outflow, with a flux density of a few times 10 8 cm −2 s −1 , was confirmed by the measurements of the Luna 2 and Explorer (1961) spacecraft (Gringauz et al 1960(Gringauz et al , 1961Bonetti et al 1963).…”

Average and unusual locations of the Earth's magnetopause and bow shock

“…Pioneer 5 (Coleman, 1964), Explorer 10 (Heppner et al, 1963;Bonetti et al, 1963) and early Soviet probes (Gringauz et al, 1961;Shklovskii et al, 1960) provided the early measurements in the boundary regions but the exploratory nature of the experiments plus limited quantities of data prevented a clear understanding of the underlying physics of the solar wind-earth interaction. The first definitive studies which included mapping of the positions of the boundaries were carried out with data from the spacecraft Explorer 12 (Chaill and Amazeen, 1963;Freeman, 1964;Cahill and 'Patel, 1967) (magnetopause only) and IMP 1 (Ness et al, 1964;Bridge et al, 1965;Wolfe et al, 1966) (magnetopause and shock).…”

“…The first definitive studies which included mapping of the positions of the boundaries were carried out with data from the spacecraft Explorer 12 (Chaill and Amazeen, 1963;Freeman, 1964;Cahill and 'Patel, 1967) (magnetopause only) and IMP 1 (Ness et al, 1964;Bridge et al, 1965;Wolfe et al, 1966) (magnetopause and shock). Subsequently the spacecraft Explorer 14 (Frank and Van Allen, 1964), IMP 2 (Fairfield and Ness, 1967;r Binsack, 1968) IMP 3 (Ness, 1967), OGO-1 (Heppner et al, 1967;Holzer et al, 1966), Vela 2A and 2B (Gosling et al, 1967) and OGO-3 (Russell et al, 1968) have further refined these measurements within 35 RE and the spacecraft Explorers 33 and 35 (Behannon, 1968(Behannon, , 1970Mihalov et al, 1970;Howe, 1970) have exten a ed the -observations to greater distances behind the The general picture revealed by all these measurements is of time dependent magnetopause and shock positions whose distances from the center.…”

Review of the Interaction Between the Geomagnetic Field and the Solar Corpuscular Radiation

“…Explorer X measurements further indicate that the "temperature" of the 8CR is between 105 and 106 oK (Bonetti et al, 1962;Rossi, 1962). According to Bocetti, et al.…”