 |
| Titel |
Coherent multiple Pc1 pulsation bands: possible evidence for the ionospheric Alfvén resonator |
| VerfasserIn |
F. Z. Feygin, A. K. Nekrasov, K. Mursula, J. Kangas, T. Pikkarainen |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 12, no. 2/3 ; Nr. 12, no. 2/3, S.147-151 |
| Datensatznummer |
250010316
|
| Publikation (Nr.) |
 copernicus.org/angeo-12-147-1994.pdf |
|
|
|
|
|
| Zusammenfassung |
| A fair fraction of Pc1 pulsation events
observed on the ground includes more than one simultaneous pulsation band. In
most such multiband events the bands display different characteristics and,
therefore, come from different source regions via horizontal ducting in the
ionosphere. However, in this report we identify a new "coherent"
subclass of multiband Pc1 events where the pearls of the simultaneous bands have
the same group velocities (repetition rates) as well as dispersion and other
properties, thus implying that the bands are produced by the same source.
Studying one example of such a coherent multiband event in more detail, we argue
that these events defy an explanation in terms of band splitting by
magnetospheric heavy ions because the observed frequency gap between the bands
is smaller than would result in such a case. We interpret these events to be due
to the frequency dependence of the ionospheric reflection coefficient of Alfvén
waves. An oscillatory frequency dependence of the coefficient is a natural
consequence of the idea that the ionosphere acts as a resonator for Alfvén
waves. We also discuss other predictions of this interpretation. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|