Fluid simulation of Jeans instability in nonthermal dusty plasmas.

Abstract

The Jeans instability is a fundamental mechanism driving the gravitational collapse and subsequent structure formation in diverse self-gravitating astrophysical environments. We present comprehensive numerical fluid simulations of the Jeans instability in a three component dusty plasma system. The high-energetic nonthermal electrons and ions are considered to follow κ distribution in velocity space with inertial dust as cold fluid. A Gaussian-type of initial density perturbation is introduced in the equilibrium density to initiate the simulations. The effects of the self-gravity parameter (α_{G}) and nonthermal spectral index (κ) on the Jeans instability have been investigated by tracking the evolution of plasma parameters in the simulations. In the absence of gravity (α_{G}=0), the system exhibits stable dust acoustic wave propagation with no Jeans instability growth, confirming pressure-dominated dynamics. Whereas, for α_{G}>0, the density increases exponentially at center of plasma system manifesting localized collapse. The nonlinear growth rates estimated from our simulations increase with α_{G} and show good agreement with the linear theory, particularly for lower α_{G} values. Simulations further demonstrate that the nonlinear growth rate is weakly dependent on κ; however, lower κ values significantly decrease the characteristic collapse time (τ_{c}). These findings establish that nonthermal (non-Maxwellian) environments in protoplanetary disks and molecular clouds are more efficient at catalyzing rapid structure formation than previously predicted by traditional thermal (Maxwellian) models.