Parallel Electric Field and Electron Acceleration: an Advanced Model
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A kinetic theory is necessary to explain the electron flows forming strong field-aligned currents in the auroral region. Its construction in this paper is based on the following propositions. (a) In the equatorial region, the arrival of electrons through the lateral surface of the magnetic flux tube is compensated for by their escape along the magnetic field. This is provided by action of the pitch-angle diffusion mechanism in the presence of plasma turbulence concentrated in this region. (b) Outside the equatorial region, the distribution functions of trapped and precipitating particles become “frozen.” The distributions and particle concentrations are calculated there in a model with conservation of the total energy and the magnetic moment. (c) The quasi-neutrality condition yields a large-scale parallel electric field, which contributes to the conserved total energy. In this field, the electron acceleration occurs, causing strong field-aligned currents directed upward from the ionosphere.
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- Antonova, E.E. and Tverskoi, B.A., The nature of the precipitation band of inverted-V type electrons and Harang discontinuity in the evening sector of the auroral ionosphere, Geomagn. Aeron., 1975, vol. 15, no. 1, pp. 105–111.Google Scholar
- Fizika verkhnei atmosfery Zemli (Physics of the Earth’s Upper Atmosphere), Ivanov-Kholodnyi, G.S., Ed., Leningrad: Gidrometizdat, 1971.Google Scholar
- Kropotkin A.P., The role of cold ionospheric plasma in the formation of the longitudinal electrostatic field on the auroral line of force, Geomagn. Aeron., 1985, vol. 25, pp. 966–970.Google Scholar
- Kropotkin, A.P., A longitudinal electrical field on auroral fieldlines in the magnetosphere, Geomagn. Aeron., 1986, vol. 26, pp. 119–122.Google Scholar
- Kropotkin, A.P. and Mart’yanov, S.A., Electric field caused by longitudinal flux of auroral electrons at an adiabatic motion of hot magnetospheric particles, Geomagn. Aeron., 1985, vol. 25, pp. 259–262.Google Scholar
- Kropotkin, A. P. and Mart’yanov, S.A., Nonstationary large-scale structure of ionospheric plasma in the region of longitudinal current running out Geomagn. Aeron., 1989, vol. 29, pp. 930–936.Google Scholar
- Mart’yanov, S.A., Features of hot magnetospheric particles fluxes related to their adiabatic motion, Geomagn. Aeron., 1982, vol. 22, pp. 686–690.Google Scholar
- Stark, C.R., Cran-McGreehin, A.P., and Wright, A.N., Contributions to the magnetospheric parallel electric field, J. Geophys. Res., 2011, vol. 116, A07216. doi 10.1029/2010JA016270Google Scholar
- Trakhtengerts, V.Y. and Demekhov, A.G., Discussion paper: Partial ring current and polarization jet, Int. J. Geomagn. Aeron., 2005, vol. 5, no. 3, GI3007. doi 10.1029/2004GI000091Google Scholar
- Trakhtengerts, V.Yu., Demekhov, A.G., Grafe, A., Fieldaligned currents in the magnetosphere caused by precipitations of energetic particles, Geomagn. Aeron. (Engl. Transl.), 1997, vol. 37, no. 4, pp. 9–16.Google Scholar
- Tverskoi, B.A., On longitudinal currents in the magnetosphere, Geomagn. Aeron., 1982, vol. 22, no. 6, pp. 991–995.Google Scholar