Abstract The plasmasphere is filled with very low energy plasma upwelling from the topside ionosphere. The field-aligned distribution of this thermal ionospheric plasma is controlled by the gravitational and centrifugal potential distribution. There are two extreme types of hydrostatic plasma distribution in this field-aligned potential : the Diffusive Equilibrium distribution and the Exospheric Equilibrium distribution corresponding respectively to a saturated and to an almost empty magnetic flux tube. As a result of pitch angle scattering by Coulomb collisions an increasing number of ions escaping from the ionosphere are stored on trapped orbits with mirror points at high altitudes in the low density region. As a result of collisions the field-aligned density distribution gradually changes from exospheric equilibrium with a highly anisotropic pitch angle (cigar like) distribution to a diffusive equilibrium with a nearly isotropic pitch angle distribution. It is shown that the suprathermal ions become anisotropic much more slowly than ions of energies smaller than 1 eV. The Coulomb collision times have been estimated for flux tubes at different L values. A numerical simulation of the flux tube refilling process has been presented. The diurnal variation of the equatorial plasma density has been illustrated for plasma elements convected along drift paths which have a large dawn- dusk asymetry. The formation of a Light Ion Trough is discussed. Finally, evidence has also been given for the existence of a ‘plasmaspheric wind’ corresponding to a slow subsonic and continuous radial expansion of the plasma stored in the plasmasphere.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Plasma transport in the plasmasphere


    Contributors:
    Lemaire, J. (author)

    Published in:

    Publication date :

    1987-01-01


    Size :

    19 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



    Plasmasphere

    Gallagher D. L. | NTIS | 2015


    The Plasmasphere

    Gallagher, D. L. | NTRS | 2015


    Breathing Plasmasphere

    D. L. Gallagher / R. H. Comfort / R. M. Katus et al. | NTIS | 2021


    The Dynamic Plasmasphere

    Moldwin, M. B. / Thomsen, M. F. / Reeves, G. D. et al. | British Library Conference Proceedings | 1997


    The Breathing Plasmasphere

    D. L. Gallagher / R. H. Comfort / R. M. Katus et al. | NTRS