Striation eigenmodes along the geomagnetic field and eigenvalues in the limit of strong ion‐neutral collisions

Abstract

A second-order linear differential reduced from the largest possible theoretical equation is derived for determining the linear value [V81k and Haerendel, 1971; Hudson and eigenmodes of striation instabilities along the Kennel, 1975b; Glassman and Sperling, 1983]. ion polarization currents can drive inductive Perkins et al., 1973; Goldman et al., 1976; tions suggest that the current patterns associated Sperling, 1983; Glassman and Sperling, 1983]. The with the instabilities cannot extend to the higher neutral density is an example of one parameter altitudes in the magnetosphere where ion Pedersen which obviously depends on altitude and position currents are negligible. A corollary remark is along the geomagnetic field.Artificial that in the earlier calculations the geomagnetic explosions in the ionosphere, such as barium field lines at higher altitudes are equipotenreleases or nuclear explosions, produce plasmas rials. The calculations presented in this paper which are nonuniform along the geomagnetic field. demonstrate that the current patterns associated Because plasma parameters are functions of the with the striation instabilities can extend into coordinate along the geomagnetic field, the ac the magnetosphere [Sperling, 1984]. conductivity is also a function of the coordinate.In the work by Goldman et al. [1976] it is Flutelike instabilities are nonuniform along the assumed that the modal potential is constant along geomagnetic field, and so their growth rates are the geomagnetic field within the unstable plasma cloud. Our calculations do not make this simplification, but rather self-consistently calculate

Dynamics of three dimensional ionospheric plasma clouds

“…The mechanism which causes the structuring of ionospheric clouds is the ExB gradient drift instability. 3 This instability has been extensively studied both theoretically [4][5][6][7][8][9] and computationally. 10 " 14 Although a considerable amount of research has been carried out on this instability, there are several deficiencies with regard to its application to ionospheric plasma clouds.…”

The Role of Finite Parallel Conductivity and Other Classical Processes on the Evolution of High-Altitude Plasmas.

“…Curves for several different values of k, (km -) are plotted in each figure. As in the nonnuclear examples discussed by Sperling and Glassman [1983], the striation eigenmodes become more localized along the geomagnetic field as the perpendicular wave number becomes larger.…”

“…Of the two cases, Case 1 is -j clearly more realistic than Case 5. Sperling and Glassman [1983], the striation eigenmodes become more localized along the geomagnetic field as the perpendicular wave number becomes larger.…”

“…~eI/Vine were to be balanced by an ion-pressure gradient. Sperling and Glassman [1983] show that (G12) provides a better estimate for kt than (Gil) for spread-F and barium clouds.…”

Finite temperature stabilization of the gradient drift instability in barium clouds

“…In this model, finite thermal effects have a stabilizing influence on short-wavelength modes. However, several studies have been performed which attempt to include parallel dynamics self-consistently in the stability analysis Sperling and Glassman, 1985;Sperling et al, 1984]. These studies incorporate the parallel length of the Copyright 1985 by the American Geophysical Union.…”