Excitation of convective cells by drift waves

Publisher Website
Google Scholar
Abstract
Parametric excitation of convective cells by drift waves is considered. Noting that the convective-cell fluctuation of the electrostatic potential is much larger than that of the density, we derive a set of coupled differential equations describing the interaction of the drift waves and the convective cells. For a weak pump, a general dispersion relation which describes three-wave decay and modulational instabilities is given. The growth rate of the latter is found to be generally smaller than that of the decay instability. Our analytical result agrees with computer simulation in which enhanced cells appear in the presence of drift-wave turbulence. The problem of anomalous cross-field diffusion is also discussed.