Correlation of magnetic fields and energetic electrons on the IMP 1 satellite

A study of simultaneous magnetic field and energetic particle records from the IMP 1 satellite on the dark side of the earth has shown several distinct correlations that can be understood as diamagnetic effects of charged particle populations. Depression of the magnetic field in the closed magnetic field line configuration of the particle cusp region is observed on most orbits. A small but significant portion of this effect can be attributed to the diamagnetic effects of electrons >45 kev. In the geomagnetic tail region, large depressions of the magnetic field having radial extent ∼10 RE are observed when the satellite approaches the neutral sheet to within ∼5 RE. Energetic electron fluxes appear throughout this volume and show no strong preference to occur immediately adjacent to the neutral sheet. In this region, less than 1% of the diamagnetic effect is due to electrons >45 kev. Finally, there are examples of intense, energetic electron fluxes closely associated with reduction of the magnetic field magnitude. In one case, an electron flux of 3×106 cm−2 sec−1 >45 kev was associated with a field change from 20 γ to 8 γ.