Abstract We have considered variations in fields and particle fluxes in the near-Earth plasma sheet on the THEMIS-D satellite together with the auroral dynamics in the satellite-conjugate ionospheric part during two substorm activations on December 19, 2014 with Kp = 2. The satellite was at ~8.5RE and MLT = 21.8 in the outer region of captured energetic particles with isotropic ion fluxes near the convection boundary of electrons with an energy of ~10 keV. During substorm activations, the satellite recorded energetic particle injections and magnetic field oscillations with a period of ~90 s. In the satellite-conjugate ionospheric part, the activations were preceded by wavelike disturbances of auroral brightness along the southern azimuthal arc. In the expansion phase of activations, large-scale vortex structures appeared in the structure of auroras. The sudden enhancements of auroral activity (brightening of arcs, auroral breakup, and appearance of NS forms) coincided with moments of local magnetic field dipolarization and an increase in the amplitude Pi2 of pulsations of the Bz component of the magnetic field on the satellite. Approximately 30–50 s before these moments, the magnetosphere was characterized by an increased rate of plasma flow in the radial direction, which initiated the formation of plasma vortices. The auroral activation delays relative to the times when plasma vortices appear in the magnetosphere decreased with decreasing latitude of the satellite projection. The plasma vortices in the magnetosphere are assumed to be responsible for the observed auroral vortex structures and the manifestation of the hybrid vortex instability (or shear flow ballooning instability) that develops in the equatorial magnetospheric plane in the presence of a shear plasma flow in the region of strong pressure gradients in the Earthward direction.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Plasma flow disturbances in the magnetospheric plasma sheet during substorm activations


    Contributors:

    Published in:

    Publication date :

    2017




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English



    Classification :

    BKL:    55.60 Raumfahrttechnik / 39.00 Astronomie: Allgemeines / 50.93 Weltraumforschung
    Local classification TIB:    770/3520/8000



    Plasma flow disturbances in the magnetospheric plasma sheet during substorm activations

    Kozelova, T. V. / Kozelov, B. V. / Turyanskii, V. A. | Springer Verlag | 2017


    Substorm Activations: Comparison of Fine Structures

    Lazutin, L. | Online Contents | 1999


    Substorm Activations: Comparison of Fine Structures

    Lazutin, L. / COSPAR; Scientific Commission D | British Library Conference Proceedings | 1999


    Magnetospheric key parameters and energy transfer during substorm

    Alexeev, I. I. | British Library Online Contents | 1996


    Magnetospheric Substorm Studies Using Balloons

    Lazutin, L. / Riedler, W. / Torkar, K. et al. | British Library Conference Proceedings | 2000