Abstract
| Language | English |
|---|---|
| Pages | 671-674 |
| Number of pages | 4 |
| Journal | Geophysical Research Letters |
| Volume | 22 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 15 Mar 1995 |
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Keywords
- dynamics
- evolution
- flows
- instability
- plasma
- waves
- ionosphere
- structure
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Vortex streets driven by sheared flow and applications to black aurora. / Shukla, P. K.; Birk, G. T.; Bingham, R.
In: Geophysical Research Letters, Vol. 22, No. 6, 15.03.1995, p. 671-674.Research output: Contribution to journal › Article
TY - JOUR
T1 - Vortex streets driven by sheared flow and applications to black aurora
AU - Shukla, P. K.
AU - Birk, G. T.
AU - Bingham, R.
PY - 1995/3/15
Y1 - 1995/3/15
N2 - Black aurora often exhibits the signature of vortex structures. In this paper, it is proposed that pseudo-three-dimensional drift-like electrostatic modes can play a very important role in those phenomena. Employing a two-fluid model, we derive a set of nonlinear equations governing the dynamics of long wavelength inertial convective cells and coupled drift-acoustic waves in the presence of geomagnetic field-aligned plasma flows. It is shown that free energy stored in the latter can cause purely growing and oscillatory instabilities in the auroral ionosphere. The threshold conditions as well as expressions for the linear growth rates are presented. Furthermore, it is found that possible stationary solutions of the nonlinear equations can be represented in the form of vortex structures. It is, therefore, likely that the nonlinear low-frequency electrostatic modes, as described here, may possibly account for the coherent vortex structures within black aurora, as they are often observed during the late recovery phase of a substorm.
AB - Black aurora often exhibits the signature of vortex structures. In this paper, it is proposed that pseudo-three-dimensional drift-like electrostatic modes can play a very important role in those phenomena. Employing a two-fluid model, we derive a set of nonlinear equations governing the dynamics of long wavelength inertial convective cells and coupled drift-acoustic waves in the presence of geomagnetic field-aligned plasma flows. It is shown that free energy stored in the latter can cause purely growing and oscillatory instabilities in the auroral ionosphere. The threshold conditions as well as expressions for the linear growth rates are presented. Furthermore, it is found that possible stationary solutions of the nonlinear equations can be represented in the form of vortex structures. It is, therefore, likely that the nonlinear low-frequency electrostatic modes, as described here, may possibly account for the coherent vortex structures within black aurora, as they are often observed during the late recovery phase of a substorm.
KW - dynamics
KW - evolution
KW - flows
KW - instability
KW - plasma
KW - waves
KW - ionosphere
KW - structure
UR - http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/(ISSN)1944-8007/
U2 - 10.1029/95GL00360
DO - 10.1029/95GL00360
M3 - Article
VL - 22
SP - 671
EP - 674
JO - Geophysical Research Letters
T2 - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 6
ER -