Quasiperiodic modulation of whistler mode waves in the inner magnetosphere

0518227 - ÚFA 2020 US eng A - Abstrakt
Němec, F. - Hospodarsky, G. - Santolík, Ondřej - Demekhov, A. - Pasmanik, D. - Bezděková, B. - Hayosh, Mykhaylo - Tomori, Alexander - Kurth, W. - Hartley, D.
Quasiperiodic modulation of whistler mode waves in the inner magnetosphere.
AGU Fall Meeting. Washington: American Geophysical Union, 2019. SM43A-06.
[AGU Fall Meeting 2019. 09.12.2019-13.12.2019, San Francisco]
Institucionální podpora: RVO:68378289
Klíčová slova: inner magnetosphere * whistler mode waves * DEMETER spacecraft * Cluster spacecraft * Van Allen Probes spacecraft
Obor OECD: Fluids and plasma physics (including surface physics)
https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/486238

Inner magnetospheric whistler mode waves at frequencies between about 0.5 and 4 kHz propagating at low wave normal angles, as well as equatorial noise emissions propagating in the equatorial plane nearly perpendicular to the ambient magnetic field at frequencies below the lower hybrid frequency, sometimes exhibit a clear quasi periodic (QP) modulation of the wave intensity. We use large sets of both types of events identified at low altitudes (DEMETER spacecraft) as well as at larger radial distances (Cluster and Van Allen Probes spacecraft) to investigate their properties and propagation. While at larger radial distances the higher frequency QP emissions are observed at all local times, at low altitudes they are observed principally during the day, indicating a nighttime propagation issue. We further investigate the modulation periods of individual events and relate them to locally measured plasma properties and possible generation mechanisms. Finally, we use the fine harmonic structure of equatorial noise emissions to identify events for which the spacecraft likely passed through the generation region, which allows us to compare the observed spectral shapes with the wave growth analysis.
Trvalý link: http://hdl.handle.net/11104/0303387