Transient, small‐scale field‐aligned currents in the plasma sheet boundary layer during storm time substorms

We report on field‐aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small‐scale field‐aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix reg...

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Detalles Bibliográficos
Autores principales: Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P.‐A., Marklund, G. T., Khotyaintsev, Y. V., Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A, Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., Saito, Y.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2016
Materias:
Research Letters
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5111425/
https://www.ncbi.nlm.nih.gov/pubmed/27867235
http://dx.doi.org/10.1002/2016GL068768
Descripción
Sumario:We report on field‐aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small‐scale field‐aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short‐lived earthward (downward) intense field‐aligned current sheets with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward/earthward during outward plasma sheet expansion. They coincide with upward field‐aligned electron beams with energies of a few hundred eV. These electrons are most likely due to acceleration associated with a reconnection jet or high‐energy ion beam‐produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.

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