 |
| Titel |
Radiation in the neighbourhood of a double layer |
| VerfasserIn |
R. Pottelette, M. Berthomier, J. Pickett |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 32, no. 6 ; Nr. 32, no. 6 (2014-06-25), S.677-687 |
| Datensatznummer |
250121074
|
| Publikation (Nr.) |
 copernicus.org/angeo-32-677-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| In the auroral kilometric radiation (AKR) source region,
acceleration layers narrow in altitude and associated with parallel field-aligned potential drops
of several kV can be identified by using both particles and
wave-field high time-resolution measurements from the Fast Auroral SnapshoT explorer spacecraft (FAST). These so-called
double layers (DLs) are recorded around density enhancements in the auroral
cavity, where the enhancement can be at the edge of the cavity or even within
the cavity at a small scale. Once immersed in the plasma, DLs necessarily
accelerate particles along the magnetic field lines, thereby generating
locally strong turbulent processes leading to the formation of nonlinear
phase space holes. The FAST data reveal the asymmetric character of the
turbulence: the regions located on the high-potential side of the DLs are
characterized by the presence of electron holes, while on the low-potential
side, ion holes are recorded. The existence of these nonlinear phase space
holes may affect the AKR radiation pattern in the neighbourhood of a DL where
the electron distribution function is drastically different from a horseshoe
shape. We present some observations which illustrate the systematic
generation of elementary radiation events occurring significantly above the
local electron gyrofrequency in the presence of electron holes. These
fine-scale AKR radiators are associated with a local electron distribution
which presents a pronounced beam-like shape. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|