 |
| Titel |
Resonant-to-nonresonant transition in electrostatic ion-cyclotron wave phase velocity |
| VerfasserIn |
J. J. Carroll III, M. E. Koepke, M. W. Zintl, V. Gavrishchaka |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1023-5809
|
| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 10, no. 1/2 ; Nr. 10, no. 1/2, S.131-138 |
| Datensatznummer |
250007828
|
| Publikation (Nr.) |
 copernicus.org/npg-10-131-2003.pdf |
|
|
|
|
|
| Zusammenfassung |
| Because of the
implications for plasmas in the laboratory and in space, attention has
been drawn to inhomogeneous energy-density driven (IEDD) waves that are
sustained by velocity-shear-induced inhomogeneity in cross-field plasma
flow. These waves have a frequency vr
in the lab frame within an order of magnitude of the ion gyrofrequency vci,
propagate nearly perpendicular to the magnetic field (kz /k^
<< 1), and can be Landau resonant (0 < v1/kz
< nd) with a parallel drifting
electron population (drift speed nd),
where subscripts 1 and r indicate frequency in the frame of
flowing ions and in the lab frame, respectively, and kz is the
parallel component of the wavevector. A transition in phase velocity from
0 < v1/kz < nd
to 0 > v1/kz > nd
for a pair of IEDD eigenmodes is observed as the degree of in-homogeneity
in the transverse E × B flow is increased in a magnetized
plasma column. For weaker velocity shear, both eigenmodes are dissipative,
i.e. in Landau resonance, with kz nd
> 0. For stronger shear, both eigenmodes become reactive, with one's
wavevector component kz remaining parallel, but with v1/kz
> nd , and the other's
wavevector component kz becoming anti-parallel, so that 0 > v1/kz
. For both eigenmodes, the transition (1) involves a small frequency shift
and (2) does not involve a sign change in the wave energy density, which
is proportional to vr v1,
both of which are previously unrecognized aspects of inhomogeneous
energy-density driven waves. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|