1 research outputs found
Parametric instability in dark molecular clouds
The present work investigates the parametric instability of parallel
propagating circularly polarized Alfven(pump) waves in a weakly ionized
molecular cloud. It is shown that the relative drift between the plasma
particles gives rise to the Hall effect resulting in the modified pump wave
characteristics. Although the linearized fluid equations with periodic
coefficients are difficult to solve analytically, it is shown that a linear
transformation can remove the periodic dependence. The resulting linearized
equations with constant coefficients are used to derive an algebraic dispersion
relation. The growth rate of the parametric instability is a sensitive function
of the amplitude of the pump wave as well as to the ratio of the pump and the
modified dust-cyclotron frequencies. The instability is insensitive to the
plasma-beta The results are applied to the molecular clouds.Comment: 27 page, 5 figures, accepted in Ap