Show simple item record

dc.contributor.authorDe Keyser, J.
dc.contributor.authorČadež, V.
dc.date2001
dc.date.accessioned2017-05-04T09:37:48Z
dc.date.available2017-05-04T09:37:48Z
dc.identifier.urihttps://orfeo.belnet.be/handle/internal/5262
dc.descriptionWe study the excitation of magnetic field fluctuations at the magnetopause by incident low-frequency waves (frequencies below the ion gyrofrequency) that are highly intermittent and that have a broad frequency spectrum, like those observed in the magnetosheath. We present simulations of the transient response of the subsolar magnetopause to such magnetosheath waves in the context of linear resistive magnetohydrodynamics (MHD) in low-beta plasmas. The incident waves excite local Alfvén waves in resonant sheets within the magnetopause transition region wherever the condition for resonant MHD wave mode conversion is satisfied. Resonant sheet locations depend on the dominant frequencies in the incident wave spectrum. Because of the intermittency of the incident waves, the resonant sheets are rarely driven to saturation. The number of resonances, their position, their thickness, and the resonant wave amplitude all vary with time in response to the temporal changes in the incident wave spectra. The net result is that the low-frequency fluctuation level at the magnetopause is enhanced throughout the transition region rather than in a single or in a few resonant sheets, while the resonant amplitudes never reach excessively high values. This also implies that a fraction of the incident wave energy is resonantly absorbed throughout the magnetopause layer, instead of the very local absorption associated with an incident monochromatic wave. Resonances never develop into very narrow length scale structures, so that the MHD approach remains justified.
dc.languageeng
dc.titleExcitation of low-frequency fluctuations at the magnetopause by intermittent broadband magnetosheath waves
dc.typeArticle
dc.subject.frascatiPhysical sciences
dc.audienceScientific
dc.source.titleJournal of Geophysical Research: Space Physics
dc.source.volume106
dc.source.issueA12
dc.source.page29467-29477
Orfeo.peerreviewedYes
dc.identifier.doi10.1029/2001JA900078
dc.identifier.scopus2-s2.0-39449137742


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record