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 K p = 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.
Similar content being viewed by others
References
Akasofu, S.-I., The development of the auroral substorm, Planet. Space Sci., 1964, vol. 12, pp. 273–282.
Donovan, E., Liu, W., Liang, J., et al., Simultaneous THEMIS in situ and auroral observations of a small substorm, Geophys. Res. Lett., 2008, vol. 35, L17S18. doi 10.1029/2008GL033794
Liang, J., Donovan, E.F., Liu, W.W., et al., Intensification of preexisting auroral arc at substorm expansion phase onset: Wave-like disruption during the first tens of seconds, Geophys. Res. Lett., 2008, vol. 35, L17S19. doi 10.1029/2008GL033666
Uritsky, V.M., Liang, J., Donovan, E., et al., Longitudinally propagating arc wave in the pre-onset optical aurora, Geophys. Res. Lett., 2009, vol. 36, L21103. doi 10.1029/2009GL040777
Chang, T.F., Cheng, C.Z., Chiang, C.Y., and Chen, A.B., Behavior of auroral arcs and Pi2 waves in December 21, 2006 substorm, Ann. Geophys., 2012, vol. 30, pp. 911–926.
Koskinen, H., Lopez, R.E., Pellinen, R.J., et al., Pseudo-breakup and substorm growth phase in the ionosphere and magnetosphere, J. Geophys. Res., 1993, vol. 98, pp. 5801–5813.
Voronkov, I.O., Donovan, E.F., and Samson, J.C., Observations of the phases of the substorm, J. Geophys. Res., 2003, vol. 108, no. A2, 1073. doi 10.1029/ 2002JA009314
McPherron, R.L., Russell, C.T., and Aubry, M.P., Satellite studies of magnetospheric substorms on August 15,1968: Phenomenological model for substorm, J. Geophys. Res., 1973, vol. 78, no. 16, pp. 3131–3149.
Sauvaud, J.-A. and Winckler, J.R., Dynamics of plasma, energetic particles, and field near synchronous orbit in the nighttime sector during magnetospheric substorms, J. Geophys. Res., 1980, vol. 85, no. A5, pp. 2043–2056.
Lazutin, L.L., Rasinkangas, R., Kozelova, T.V., et al., Observations of substorm fine structure, Ann. Geophys., 1998, vol. 16, no. 7, pp. 775–786.
Liou, K., Meng, C.-I., Newell, P.T., et al., Particle injections with auroral expansions, J. Geophys. Res., 2001, vol. 106, pp. 5873–5881.
Steen, Å. and Collis, P.N., High time-resolution imaging of auroral arc deformation at substorm onset, Planet. Space Sci., 1988, vol. 36, no. 7, pp. 715–732.
Elphinstone, R.D., Hearn, D.J., Cogger, L.L., et al., Observations in the vicinity of substorm onset: Implications for the substorm process, J. Geophys. Res., 1995, vol. 100, pp. 7937–7969. doi 10.1029/94JA02938
Samson, J.C., Cogger, L.L., and Pao, Q., Observations of field line resonances, auroral arcs, and auroral vortex structures, J. Geophys. Res., 1996, vol. 101, pp. 17373–17383.
Keiling, A., Angelopoulos, V., Runov, A., et al., Substorm current wedge driven by plasma flow vortices: THEMIS observations, J. Geophys. Res., 2009, vol. 114, A00C22. doi 10.1029/2009JA014114
Keiling, A., Angelopoulos, V., Weygand, J.M., et al., THEMIS ground–space observations during the development of auroral spirals, Ann. Geophys., 2009, vol. 27, no. 11, pp. 4317–4332.
Voronkov, I., Rankin, R., Frycz, P., et al., Coupling of shear flow and pressure gradient instabilities, J. Geophys. Res., 1997, vol. 102, no. A5, pp. 9639–9650. doi 10.1029/97JA00386
Roux, A., Perraut, S., Robert, P., et al., Plasma sheet instability related to the westward traveling surge, J. Geophys. Res., 1991, vol. 96, pp. 17697–17714. doi 10.1029/91JA01106
Holter, O., Altman, C., Roux, A., et al., Characterization of low frequency oscillations at substorm breakup, J. Geophys. Res., 1995, vol. 100, pp. 19109–19119.
Erickson, G.M., Maynard, N.C., Wilson, G.R., and Burke, W.J., Electromagnetics of substorm onsets in the near-geosynchronous plasma sheet, J. Geophys. Res., 2000, vol. 105, pp. 25265–25290. doi 10.1029/ 1999JA000424
Kozelova, T.V. and Kozelov, B.V., Substorm-associated explosive magnetic field stretching near the earthward edge of the plasma sheet, J. Geophys. Res., 2013, vol. 118, pp. 3323–3335. doi 10.1002/jgra.50344
Chang, T.-F. and Cheng, C.-Z., Relationship between wave-like auroral arcs and Pi2 disturbances in plasma sheet prior to substorm onset, Earth Planets Space, 2015, vol. 67, 168. doi 10.1186/s40623-015-0334-8
Timofeev, E.E., Vallinkoski, M.K., Kozelova, T.V., et al., Systematics of arc-associated electric fields and currents as inferred from radar backscatter measurements, Z. Geophys., 1987, vol. 61, no. 2, pp. 122–137.
Kerns, K.J., Hardy, D.A., and Gussenhoven, M.S., Modeling of convection boundaries seen by CRRES in 120-eV to 28-keV particles, J. Geophys. Res., 1994, vol. 99, no. A2, pp. 2403–2414.
Walker, R.J., Erickson, K.N., Swanson, R.L., and Winckler, J.R., Substorm associated particle boundary motion at synchronous orbit, J. Geophys. Res., 1976, vol. 31, pp. 5541–5550.
Voronkov, I., Donovan, E.F., Jackel, B.J., and Samson, J.C., Large-scale vortex dynamics in the evening and midnight auroral zone: Observations and simulations, J. Geophys. Res., 2000, vol. 105, pp. 18505–18518.
Aikio, A.T., Opgenoorth, H.J., Persson, M.A.L., and Kaila, K.U., Ground-based measurements of an arcassociated electric field, J. Atmos. Terr. Phys., 1993, vol. 55, pp. 797–808.
Amm, O., Ionospheric elementary current systems in spherical coordinates and their application, J. Geomagn. Geoelectr., 1997, vol. 49, pp. 947–955.
Shiokawa, K., Baumjohann, W., and Haerendel, G., Braking of highspeed flows in the near-Earth tail, Geophys. Res. Lett., 1997, vol. 24, pp. 1179–1182. doi 10.1029/97GL01062
Birn, J., Hesse, M., Haerendel, G., et al., Flow braking and the substorm current wedge, J. Geophys. Res., 1999, vol. 104, pp. 19895–19903. doi 10.1029/1999JA900173
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © T.V. Kozelova, B.V. Kozelov, V.A. Turyanskii, 2017, published in Kosmicheskie Issledovaniya, 2017, Vol. 55, No. 6, pp. 438–447.
Rights and permissions
About this article
Cite this article
Kozelova, T.V., Kozelov, B.V. & Turyanskii, V.A. Plasma flow disturbances in the magnetospheric plasma sheet during substorm activations. Cosmic Res 55, 426–435 (2017). https://doi.org/10.1134/S0010952517060065
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0010952517060065