Abstract
We report on the results of 2- and 3-dimentional numerical
investigations of the evolution of samarium ion clouds injected in the
equatorial ionosphere, alike the recent MOSC experiments. The ambient
conditions are described by a standard model of the quiet-time
equatorial ionosphere from 90 to 350 km. The altitudinal distribution of
the transport processes and ambient electric and magnetic fields is
taken into account. The fast process of stratification of ion clouds and
breaking into small plasmoids occur only during the late stage of the
cloud evolution. The role of the background plasma and its depletion
zones formed due to the short-circuiting currents is not as evident as
in mid latitudes. It is also revealed that the altitudinal dependence of
the diffusion and drift plays a minor role in the cloud evolution at the
equator. Likewise, the cloud remains stable with respect to the
Raleigh-Taylor and gradient-drift instabilities. These two features are
defined by the equatorial near-horizontal magnetic field which leads to
a strongly-elongated ellipsoid-like plasma cloud. The critical dip angle
separating the stable (equatorial) and unstable (mid-latitude) cloud
regimes will be defined in future simulation studies, as well as the
dependence on the ambient electric field and neutral wind.
2Space Vehicles Directorate, Air Force Research Laboratory
| Original language | English |
|---|---|
| Title of host publication | APS Division of Plasma Physics Meeting 2015 |
| State | Published - 1 Nov 2015 |