 |
| Titel |
Parallel electric field in the auroral ionosphere: excitation of acoustic waves by Alfvén waves |
| VerfasserIn |
P. L. Israelevich, L. Ofman |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 22, no. 8 ; Nr. 22, no. 8 (2004-09-07), S.2797-2804 |
| Datensatznummer |
250014966
|
| Publikation (Nr.) |
 copernicus.org/angeo-22-2797-2004.pdf |
|
|
|
|
|
| Zusammenfassung |
| We investigate a new mechanism for the formation of a parallel electric field
observed in the auroral ionosphere. For this purpose, the excitation of
acoustic waves by propagating Alfvén waves was studied numerically. We
find that the magnetic pressure perturbation due to finite amplitude
Alfvén waves causes the perturbation of the plasma pressure that
propagates in the form of acoustic waves, and gives rise to a parallel
electric field. This mechanism explains the observations of the strong
parallel electric field in the small-scale electromagnetic perturbations of
the auroral ionosphere. For the cases when the parallel electric current in
the small-scale auroral perturbations is so strong that the velocity of
current carriers exceeds the threshold of the ion sound instability, the
excited ion acoustic waves may account for the parallel electric fields as
strong as tens of mV/m. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|