Heavy ion measurements in the synchronous altitude region

Abstract

The launch of the P78-2 (SCATHA) satellite in January 1979 has provided a new opportunity to study the energetic ion composition in the high altitude equatorial regions of the earth's magnetosphere. In particular detailed pitch angle distributions were obtained as a function of ion species and energy. The energies measured range from ∼ 90 to 250 keV/nucleon for Z ⩾ 2. Data are presented which were acquired in late March and early April 1979. The relative abundance of He and CNO nuclei are found to be ∼ 10 −2 and 5 × 10 −4 respectively at L ≅ 5.5. Only an upper limit on the relative abundance of Fe group nuclei of < 3 × 10 −7 was obtained. The angular distributions of the heavy ions was found to be very steep for B B 0 < 1.5 and then to flatten markedly.