On February 10, 1991, the CRRES spacecraft measured substorm related E- and B-field variations and high energy particle fluxes at r ∼ 5 RE and 22h MLT at the magnetic equator. Just following the substorm onset, a few strong (∼ 2 mV/m) pulses of westward E-field appeared at CRRES, well before any large effects on particle fluxes and magnetic field. These pulses occurred simultanously with the onsets of energetic plasma injections at 6.6 RE (LANL data). Thus the impulsive electric field propagated inward from the current disruption region very fast, possibly as a fast magnetosonic wave. After ∼ 6 min delay from the substorm onset, a complicated pattern of nondispersive energetic particle injection and signatures of magnetic field dipolarization appeared at CRRES location. We interpret this pattern as a two-layered spatial configuration transported inward approximately at the convection speed. The first layer consisted of mostly high energy (> 100 keV) protons whose diamagnetic effect explains the observed magnetic field depression (the so-called Explosive Growth Phase signature). It had a thickness of about a few proton gyroradii. The second (adjacent) layer was characterized by magnetic field dipolarization and increase of energetic electron fluxes. Utilizing the multipoint multi-instrumental observations, we specified the radial distribution of particle fluxes and magnetic field to compute the particle flux variations resulting from the inward convective transport.

Original languageEnglish
Pages (from-to)573-578
Number of pages6
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number389
StatePublished - 1 Dec 1996

    Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science

ID: 36728328