Atypical gravito-electrostatic fluctuations in the presence of active ion-inertial dynamics

Abstract

The plasmas in space, cosmic and astrophysical environments are long known to consist of numerous massive ionic components contributing to various wave instability fluctuation phenomena. Indeed, the ion-inertial effects need to be incorporated into realistic analyses, rather than treating the gravitating ionic species traditionally as a Boltzmann distributed fluid. Herein, we present an atypical theoretical model setup to study gravito-electrostatic mode-fluctuations in self-gravitating inhomogeneous interstellar dust molecular clouds (DMCs) on the astrophysical fluid scales of space and time. The main goal is focused on investigating the influence of self-consistent dynamic ion-inertial effects on the stability. Methodological application of standard multiple scaling techniques reduces the basic plasma structure equations into a unique pair of decoupled Korteweg–de Vries (KdV) equations for the weak fluctuations. In contrast, the fully nonlinear counterparts are shown to evolve as a new gravito-electrostatically coupled pair of the Sagdeev energy-integral equations. In both the perturbation regimes, excitation of two distinct eigenmode classes – electrostatic compressive solitons and self-gravitational rarefactive solitons with unusual and unique parametric features – is demonstrated and portrayed. The graphical shape analysis reflects new plasma conditions for such eigenspectral patterns to coevolve in realistic interstellar parameter windows hitherto remaining unexplored. It is seen that the inertial ions play a destabilizing influential role leading to enhanced fluctuations toward establishing a reorganized gravito-electrostatic equilibrium structure. Finally, we discuss the consistency of our results in the framework of existing inertialess ion theories, experimental findings and multiple space satellite-based observations, together with new implications.

Nonlinear Waves in Nonuniform Complex Astrocloud

“…It consists of warm lighter electrons and ions, and massive positively-negatively charged dust grains amid partial ionization. It relaxes the Jeansian swindle [18,23] against the usual viewpoint. Electrons and ions are assumed to be inertialess, dictated by the pure Boltzmann distribution laws, on the Jeans scales.…”

“…Analogous grain-driven dynamic patterns have been found to exist in different cosmic and astrospace regions [13,16,17]. In the latter, the wave dynamics has been triggered by the unusual coupling between self-gravitational attraction (Newtonian grains, inertial) and electrostatic repulsion (Coulombic grains, homopolar) in diverse generalized polytropic plasma configurations [10,14,18].…”

“…Thus, the inhomogeneous self-gravitational fluctuations too, analogous to the electrostatic counterparts (eq. (42)), are governed by equation (47) 47)) is implanted in the inhomogeneous equilibrium build up with the Jeans swindle [18] absolutely relaxed. In a simplified case however, if the homogeneous equilibrium were considered instead, with insignificant gradient correction, a different form of the KdV-family equation, with no zeroth-order gradient effects, would have resulted.…”

Bimodal pair f-KdV dynamics in star-forming clouds

“…-We propose to study the weakly nonlinear bimodal fluctuation dynamics with a procedurally derived conjugational pair of the forced Korteweg-de Vries (f -KdV) equations. As a first step, we apply a multi-scale analysis [4,6,18,19] in a new stretched (slow) coordinate system defined by a pair of coordinates as ξ := 1/2 (X − μT ) for space and as τ := 3/2 T for time. Here, is a smallness (order) parameter (0 < < 1) typifying the strength of nonlinearity arising due to fluid convection (or the weakness of linear dispersion due to deviation from quasi-neutrality).…”

“…It is now seen that eqs. (19), (20) are analytically nonintegrable and unsolvable due to the co-involved nonlinear complications. A numerical platform, therefore, is constructed for analysing the exact patterns of the fluctuations of interest.…”