NONLINEAR LANGMUIR-WAVES IN 2-ELECTRON-TEMPERATURE PLASMAS

We investigate the stationary propagation of nonlinear Langmuir waves in a bi-Maxwellian plasma consisting of two-electron-species in the cr itical parameter regime (Delta = 3). It is shown that there exists a n ew class of Langmuir envelope waves which have qualitatively different structure from the solutions reported earlier. In particular, the Lan gmuir held envelope has two nodes, and accordingly the field intensity has a triple-hump structure. The low-frequency density perturbation w hich traps the Langmuir held has the usual single-dip structure. The c oupled fields co-propagate with supersonic speeds but are accompanied by density rarefactions.