Energy spectra of auroral zone particles

Two sounding rockets were launched into auroral breakups near local midnight and one rocket was launched into a 2.5-db riometer absorption event at local noon. The rockets were instrumented to measure the energy spectra of electrons and protons. Results show that electron fluxes in the auroral zone resemble electron fluxes in the plasma sheet, both in the shape of energy spectra and in the magnitude of flux, which indicates that the plasma sheet may be the source of auroral zone electrons. The proton fluxes in these two regions are quite different. Thus the plasma sheet probably is not the source of auroral zone protons. Time variations of 1-kev electrons and protons were coherent, which indicates similar precipitation mechanisms for these two types of particles. The source of 1-kev electrons was found to have a wider spatial extent than the source of 10-kev electrons. During auroral breakup, electron precipitation was isotropic over the upper hemisphere while the protons were anisotropic, with more flux at 90° than at 0°.