Drift solitons

Abstract

The theory of the drift solitons is revised. It shows the error of the conclusion of V.N. Oraevskii et al. (1969) that the presence of an electron temperature gradient is the necessary condition for the existence of the drift solitons. It is elucidated here that for the correct analysis of the problem of the drift solitons, the vector nonlinearity must be taken into account. The conclusion is drawn, that the drift solitons may exist in a plasma with a homogeneous temperature. The experiments confirming this conclusion are noted. It is shown that for the existence of the drift solitons a sufficiently high level of the drift activity is necessary, which is characterized by the qualitative relation n/n_o>or approximately=1/k_{perpendicular to} L_n, where n and n_o are the perturbed and equilibrium parts of the plasma number density, k_{perpendicular to} is the characteristic transverse wave number of the soliton L_n the characteristic scale of inhomogeneity of the plasma number density. Some generalizations of the simplest theory of the drift solitons are considered when taking into account the solitons of both the oblique drift waves and short-wavelength drift waves, and also taking into account the effect of the cubic nonlinearity.