Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause

Our purpose is to characterize the evolution of the magnetopause Kelvin-Helmholtz (KH) wave activity with changes in thickness of the adjacent boundary layer, geomagnetic latitude and interplanetary magnetic field (IMF) orientation. As the IMF turns northward, wave activity may be generated at the d...

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Autores principales: Foullon, C., Farrugia, C.J., Fazakerley, A.N., Owen, C.J., Gratton, F.T., Torbert, R.B.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_21699402_v113_n11_p_Foullon
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_21699402_v113_n11_p_Foullon2023-10-03T16:40:08Z Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause Foullon, C. Farrugia, C.J. Fazakerley, A.N. Owen, C.J. Gratton, F.T. Torbert, R.B. Our purpose is to characterize the evolution of the magnetopause Kelvin-Helmholtz (KH) wave activity with changes in thickness of the adjacent boundary layer, geomagnetic latitude and interplanetary magnetic field (IMF) orientation. As the IMF turns northward, wave activity may be generated at the dayside before propagating down the tail, where the boundary layer is expected to support longer wavelengths. We use two-point observations on the dusk magnetopause at low latitudes, from Geotail on the dayside and Cluster tailward of the dusk terminator. We quantify the wavelength, power, wavefront steepness and propagation direction at Cluster. An estimate of the thickness of the low-latitude boundary layer (LLBL) is obtained by correlating normal distances to the magnetopause, derived from two empirical solar-wind-driven models, with a systematic relationship (the "transition parameter") found between the electron number density and temperature; the correlation factor is used to infer the temporal evolution of the thickness of the locally sampled layer. We find that wavelengths are controlled by the IMF clock angle, as expected when generated by the KH mechanism at the dayside, although amplitudes, wavefront steepness and propagation directions are more closely correlated with the layer thickness. A survey of parameter space provides evidence of the contribution of the KH mechanism to the widening of the electron LLBL. Copyright 2008 by the American Geophysical Union. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_21699402_v113_n11_p_Foullon
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description Our purpose is to characterize the evolution of the magnetopause Kelvin-Helmholtz (KH) wave activity with changes in thickness of the adjacent boundary layer, geomagnetic latitude and interplanetary magnetic field (IMF) orientation. As the IMF turns northward, wave activity may be generated at the dayside before propagating down the tail, where the boundary layer is expected to support longer wavelengths. We use two-point observations on the dusk magnetopause at low latitudes, from Geotail on the dayside and Cluster tailward of the dusk terminator. We quantify the wavelength, power, wavefront steepness and propagation direction at Cluster. An estimate of the thickness of the low-latitude boundary layer (LLBL) is obtained by correlating normal distances to the magnetopause, derived from two empirical solar-wind-driven models, with a systematic relationship (the "transition parameter") found between the electron number density and temperature; the correlation factor is used to infer the temporal evolution of the thickness of the locally sampled layer. We find that wavelengths are controlled by the IMF clock angle, as expected when generated by the KH mechanism at the dayside, although amplitudes, wavefront steepness and propagation directions are more closely correlated with the layer thickness. A survey of parameter space provides evidence of the contribution of the KH mechanism to the widening of the electron LLBL. Copyright 2008 by the American Geophysical Union.
format JOUR
author Foullon, C.
Farrugia, C.J.
Fazakerley, A.N.
Owen, C.J.
Gratton, F.T.
Torbert, R.B.
spellingShingle Foullon, C.
Farrugia, C.J.
Fazakerley, A.N.
Owen, C.J.
Gratton, F.T.
Torbert, R.B.
Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause
author_facet Foullon, C.
Farrugia, C.J.
Fazakerley, A.N.
Owen, C.J.
Gratton, F.T.
Torbert, R.B.
author_sort Foullon, C.
title Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause
title_short Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause
title_full Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause
title_fullStr Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause
title_full_unstemmed Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause
title_sort evolution of kelvin-helmholtz activity on the dusk flank magnetopause
url http://hdl.handle.net/20.500.12110/paper_21699402_v113_n11_p_Foullon
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