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Titolo:
Transient development of magnetohydrodynamic wave mode conversion layers
Autore:
De Keyser, J; Cadez, V;
Indirizzi:
Belgian Inst Space Aeron, B-1180 Brussels, Belgium Belgian Inst Space Aeron Brussels Belgium B-1180 -1180 Brussels, Belgium
Titolo Testata:
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
fascicolo: A8, volume: 106, anno: 2001,
pagine: 15609 - 15619
SICI:
0148-0227(20010801)106:A8<15609:TDOMWM>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
MAGNETIC-FLUX TUBES; FIELD LINE RESONANCES; ALFVEN WAVES; MHD WAVES; SUBSOLAR MAGNETOPAUSE; PLASMA-WAVES; SLOW WAVES; ABSORPTION; FLUCTUATIONS; MAGNETOSHEATH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: De Keyser, J Belgian Inst Space Aeron, Ringlaan 3, B-1180 Brussels, Belgium Belgian Inst Space Aeron Ringlaan 3 Brussels Belgium B-1180
Citazione:
J. De Keyser e V. Cadez, "Transient development of magnetohydrodynamic wave mode conversion layers", J GEO R-S P, 106(A8), 2001, pp. 15609-15619

Abstract

We study the transmission, reflection, and absorption of ultralow frequency waves at density nonuniformities in low beta plasmas, such as plasma structures in the solar corona, inhomogeneities in the solar wind, and, at times, in the magnetopause. We simulate the time-dependent interaction of a monochromatic magnetohydrodynamic (MHD) wave with a planar plasma transition layer aligned with the magnetic field. When the incident wave front reaches the initially unperturbed transition layer, a resonant sheet starts to develop within a thin layer where the conditions for resonant MHD wave mode conversion are satisfied. In this sheet the wave amplitude is found to grow exponentially until a saturation level is reached due to dissipative effects. Dissipation controls the thickness of the sheet, the saturation level, andthe time needed to reach the saturation regime. The resonantly absorbed energy, however, is essentially independent of the dissipation coefficient. The simulations are carried out in the context of linear resistive low beta magnetohydrodynamics. The simulation results are important for the case of the magnetopause as the enhanced wave amplitudes found inside the transition could promote diffusive mass transport across the layer.

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Documento generato il 02/04/20 alle ore 02:54:03