Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations

Mostrar todas las versiones(3)

The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999) allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time) at a radial distance of 24 to 30 RE (Earth radii). Duri...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Farrugia, C.J., Gratton, F.T., Gnavi, G., Matsui, H., Torbert, R.B., Fairfield, D.H., Ogilvie, K.W., Lepping, R.P., Terasawa, T., Mukai, T., Saito, Y.
Formato: Artículo publishedVersion
Publicado: 2005
Materias:
Ionosphere (Wave-particle interactions)
Magnetospheric physics (Magnetosheath)
Radio science (Waves in plasma)
magnetosphere
solar wind
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09927689_v23_n4_p1317_Farrugia
https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_09927689_v23_n4_p1317_Farrugia_oai
Aporte de:
Repositorio Digital de la Universidad de Buenos Aires (UBA) de Universidad de Buenos Aires
id I28-R145-paper_09927689_v23_n4_p1317_Farrugia_oai
record_format dspace
spelling I28-R145-paper_09927689_v23_n4_p1317_Farrugia_oai2024-08-16 Farrugia, C.J. Gratton, F.T. Gnavi, G. Matsui, H. Torbert, R.B. Fairfield, D.H. Ogilvie, K.W. Lepping, R.P. Terasawa, T. Mukai, T. Saito, Y. 2005 The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999) allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time) at a radial distance of 24 to 30 RE (Earth radii). During most of this period, interplanetary parameters varied gradually and in such a way as to give rise to two extreme magnetosheath structures, one dominated by magnetohydrodynamic (MHD) effects and the other by gas dynamic effects. We focus attention on unusual features of electromagnetic ion wave activity in the former magnetosheath state, and compare these features with those in the latter. Magnetic fluctuations in the gas dynamic magnetosheath were dominated by compressional mirror mode waves, and left-and right-hand polarized electromagnetic ion cyclotron (EIC) waves transverse to the background field. In contrast, the MHD magnetosheath, lasting for over one day, was devoid of mirror oscillations and permeated instead by EIC waves of weak intensity. The weak wave intensity is related to the prevailing low solar wind dynamic pressures. Left-hand polarized EIC waves were replaced by bursts of right-hand polarized waves, which remained for many hours the only ion wave activity present. This activity occurred when the magnetosheath proton temperature anisotropy (=Tp, ⊥/Tp, ∥-1) became negative. This was because the weakened bow shock exposed the magnetosheath directly to the (negative) temperature anisotropy of the solar wind. Unlike the normal case studied in the literature, these right-hand waves were not by-products of left-hand polarized waves but derived their energy source directly from the magnetosheath temperature anisotropy. Brief entries into the low latitude boundary layer (LLBL) and duskside magnetosphere occurred under such inflated conditions that the magnetospheric magnetic pressure was insufficient to maintain pressure balance. In these crossings, the inner edge of the LLBL was flowing sunward. The study extends our knowledge of magnetosheath ion wave properties to the very low solar wind dynamic pressure regime. © European Geosciences Union 2005. Fil:Gratton, F.T. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Gnavi, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. application/pdf http://hdl.handle.net/20.500.12110/paper_09927689_v23_n4_p1317_Farrugia info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar Ann. Geophys. 2005;23(4):1317-1333 Ionosphere (Wave-particle interactions) Magnetospheric physics (Magnetosheath) Radio science (Waves in plasma) magnetosphere solar wind Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_09927689_v23_n4_p1317_Farrugia_oai
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-145
collection Repositorio Digital de la Universidad de Buenos Aires (UBA)
topic Ionosphere (Wave-particle interactions)
Magnetospheric physics (Magnetosheath)
Radio science (Waves in plasma)
magnetosphere
solar wind
spellingShingle Ionosphere (Wave-particle interactions)
Magnetospheric physics (Magnetosheath)
Radio science (Waves in plasma)
magnetosphere
solar wind
Farrugia, C.J.
Gratton, F.T.
Gnavi, G.
Matsui, H.
Torbert, R.B.
Fairfield, D.H.
Ogilvie, K.W.
Lepping, R.P.
Terasawa, T.
Mukai, T.
Saito, Y.
Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations
topic_facet Ionosphere (Wave-particle interactions)
Magnetospheric physics (Magnetosheath)
Radio science (Waves in plasma)
magnetosphere
solar wind
description The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999) allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time) at a radial distance of 24 to 30 RE (Earth radii). During most of this period, interplanetary parameters varied gradually and in such a way as to give rise to two extreme magnetosheath structures, one dominated by magnetohydrodynamic (MHD) effects and the other by gas dynamic effects. We focus attention on unusual features of electromagnetic ion wave activity in the former magnetosheath state, and compare these features with those in the latter. Magnetic fluctuations in the gas dynamic magnetosheath were dominated by compressional mirror mode waves, and left-and right-hand polarized electromagnetic ion cyclotron (EIC) waves transverse to the background field. In contrast, the MHD magnetosheath, lasting for over one day, was devoid of mirror oscillations and permeated instead by EIC waves of weak intensity. The weak wave intensity is related to the prevailing low solar wind dynamic pressures. Left-hand polarized EIC waves were replaced by bursts of right-hand polarized waves, which remained for many hours the only ion wave activity present. This activity occurred when the magnetosheath proton temperature anisotropy (=Tp, ⊥/Tp, ∥-1) became negative. This was because the weakened bow shock exposed the magnetosheath directly to the (negative) temperature anisotropy of the solar wind. Unlike the normal case studied in the literature, these right-hand waves were not by-products of left-hand polarized waves but derived their energy source directly from the magnetosheath temperature anisotropy. Brief entries into the low latitude boundary layer (LLBL) and duskside magnetosphere occurred under such inflated conditions that the magnetospheric magnetic pressure was insufficient to maintain pressure balance. In these crossings, the inner edge of the LLBL was flowing sunward. The study extends our knowledge of magnetosheath ion wave properties to the very low solar wind dynamic pressure regime. © European Geosciences Union 2005.
format Artículo
Artículo
publishedVersion
author Farrugia, C.J.
Gratton, F.T.
Gnavi, G.
Matsui, H.
Torbert, R.B.
Fairfield, D.H.
Ogilvie, K.W.
Lepping, R.P.
Terasawa, T.
Mukai, T.
Saito, Y.
author_facet Farrugia, C.J.
Gratton, F.T.
Gnavi, G.
Matsui, H.
Torbert, R.B.
Fairfield, D.H.
Ogilvie, K.W.
Lepping, R.P.
Terasawa, T.
Mukai, T.
Saito, Y.
author_sort Farrugia, C.J.
title Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations
title_short Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations
title_full Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations
title_fullStr Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations
title_full_unstemmed Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations
title_sort magnetosheath waves under very low solar wind dynamic pressure: wind/geotail observations
publishDate 2005
url http://hdl.handle.net/20.500.12110/paper_09927689_v23_n4_p1317_Farrugia
https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_09927689_v23_n4_p1317_Farrugia_oai
work_keys_str_mv AT farrugiacj magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT grattonft magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT gnavig magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT matsuih magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT torbertrb magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT fairfielddh magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT ogilviekw magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT leppingrp magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT terasawat magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT mukait magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
AT saitoy magnetosheathwavesunderverylowsolarwinddynamicpressurewindgeotailobservations
_version_ 1809357105584406528

Ejemplares similares