Journal of Geophysical Research, vol. 79, Feb. 1, 1974, p. 549-553.
Calculations are made to determine what changes are expected in auroral electron energy spectra and pitch angle distributions, as seen at low altitudes, when the tail collapses from an extended to a dipolar configuration. The calculations begin with an isotropic Maxwell-Boltzmann distribution and assume that electrons move toward the earth while the first two adiabatic invariants are conserved. A model for plasma and field line motion is chosen to approximate motions that have been observed during substorms. The energy distribution remains Maxwellian, and both the energy of an individual electron and the Maxwell-Boltzmann characteristic energy increase by the same ratio as electrons move to lower field lines. There is a general tendency for electron fluxes to become slightly peaked at 90 deg if the first two invariants are conserved during acceleration. A brief comparison with data from rockets and low-altitude satellites suggests that electrons may often be accelerated by this mechanism.
Major Subject Terms: ELECTRON ENERGY, GEOMAGNETIC TAIL, MAGNETIC FIELD CONFIGURATIONS, MATHEMATICAL MODELS, MAXWELL- BOLTZMANN DENSITY FUNCTION, PARTICLE ACCELERATION
Minor Subject Terms: ATMOSPHERIC MODELS, AURORAL ZONES, COLLAPSE, ENERGY DISTRIBUTION, MAGNETIC DIPOLES, MAGNETIC STORMS
CASI Accession Number: A7421684 ISSN