INFINA (EX INFIP)   05545
INSTITUTO DE FISICA INTERDISCIPLINARIA Y APLICADA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Aspects of Magnetopause/Magnetosphere Response to Interplanetary Discontinuites, and Features of Magnetopause Kelvin-Helmholtz Waves. Farrugia
Autor/es:
FARRUGIA, C. J.; GRATTON, F. T.
Lugar:
San Francisco
Reunión:
Congreso; 2008 AGU Fall Meeting; 2008
Institución organizadora:
AGU
Resumen:
We review some recent work on (i) the reponse of the magnetosphere to impinging interplanetary discontinuities, and (ii) the excitation of surface waves of Kelvin-Helmholtz (KH) origin at the magnetopause. The work will be concerned with strongly northward-pointing IMF. Data from various spacecraft are discussed and KH activity is analyzed using compressible, linearized MHD theory. In one example, the products of sudden and large--amplitude pressure changes interacting with the bow shock are studied by two-spacecraft observations in the near flanks. We show that the wave in the boundary layer propagates down the tail faster than the pressure front in the magnetosheath, resulting in motions and distortions of the magnetopause boundary which precede the arrival of the magnetosheath front. We then discuss an example of KH waves observed at the flankside magnetopause during passage of the rear end of a magnetic cloud. We argue that these waves are generated remotely at the dayside. The magnetopause KH waves are monitored from the magnetosheath where they appear as an envelope modulation of the magnetosonic waves. A drift to lower frequencies (longer wavelengths) in the spectral power of the KH activity is attributed to a decrease in the IMF clock angle. Finally, we discuss features of the two-stage magnetopause/magnetosphere response elicited by a joint solar wind tangential discontinuity/vortex sheet followed by an interval of northward IMF. This work is supported by NASA grant NNX08AD11G, NASA Cluster grant to UNH, and by Argentine CONICET grant PIP 5291/05.