Molecular Cloud Formation Via Thermal Instability of Finite Resistive Viscous Radiating Plasma with Finite Larmor Radius Corrections

摘要

The effect of radiative heat-loss function and finite ion Larmor radius (FLR)corrections on the thermal instability of infinite homogeneous viscous plasmahas been investigated incorporating the effects of thermal conductivity andfinite electrical resistivity for the formation of a molecular cloud. Thegeneral dispersion relation is derived using the normal mode analysis methodwith the help of relevant linearized perturbation equations of the problem.Furthermore the wave propagation along and perpendicular to the direction ofexternal magnetic field has been discussed. Stability of the medium isdiscussed by applying Routh Hurwitzs criterion and it is found that thermalinstability criterion determines the stability of the medium. We find that thepresence of radiative heat-loss function and thermal conductivity modify thefundamental criterion of thermal instability into radiatively driven thermalinstability criterion. In longitudinal direction FLR corrections, viscosity,magnetic field and finite resistivity have no effect on thermal instabilitycriterion. The presence of radiative heat-loss function and thermalconductivity modify the fundamental thermal instability criterion intoradiatively driven thermal instability criterion. Also the FLR correctionsmodify the growth rate of the Alfven mode. For transverse wave propagation FLRcorrections, radiative heat-loss function, magnetic field and thermalconductivity modify the thermal instability criterion. From the curves it isclear that heat-loss function, FLR corrections and viscosity have stabilizingeffect, while finite resistivity has destabilizing effect on the thermal modes.Our results show that the FLR corrections and radiative heat-loss functionsaffect the evolution of interstellar molecular clouds and star formation.