Study On The Plasma Waves Dynamics In Milicharged Dark Matter-plasma System

As the closely related cross area of the astrophysics and the plasma physics,the dark matter is always the main point of research.We know that the charge mass of dark matter is much more smaller than the charge-to-mass ratio of the electron or proton,it could deduce that there may be small Electromagnetic charge for the dark matter,which this candidate,commonly known as millicharged dark matter(m DM),would form a plasma and interact with the interstellar medium and electromagnetic fields within galaxies.Then,it is still a mystery about its origin and composition.Generally,the process of comprehending dynamics of m DM requires consideration of collective plasma effects.It has been proposed that m DM can be accelerated in supernova remnants,forming a dark cosmic ray population that would leave distinct experimental signals.Considering the galaxies are self-gravitating systems which consist of many collisionless particles,the one of the methods of statistical mechanics is able to be used to infer the systems of stellar distribution function.Actually,the long-range nature of the gravitational force contrasts starkly with the underlying hypothesis of Boltzmann statistics in which the interactions among particles are assumed to be short-ranged.A particular generalization of the classical Boltzmann formalism is available within the non-extensive context of Tsallis q-statistics,subjecting to the non-additivity of the entropies of subsystems.In this paper,the dispersions and Landau damping of the ion acoustic waves in the dark plasma system with non-extensive distribution millicharged dark matter particles are investigated under the kinetic theory regimes.The parameters of the Landau damping of the waves relate to the parameter q of the distribution function.However,the growth rate,due to the streaming dark matter,is acutely tiny,compared with the damping rates arising from the electrons and ions.Therefore,both Maxwellian and non-extensive distributions are strongly controlled by the dark matter.Hence,the waves cannot be stimulated yet.Furthermore,we restudy the Jeans instability in a self-gravitational system composed of dark and bright matter,based on the framework of non-extensive statistics and its kinetic theory.The result indicates there is significant effect the dynamics of the Jeans modes,which is caused by Millicharged dark matter under a non-extensive distribution.The parameter q increasing,the system will be more stable.As expectation,when the q →1,the obtained results will restore to those of Boltzmann statistics.This result may provide a new idea for understanding the intrinsic physical mechanisms of cloud collapse in interstellar gas,and for astrophysics and dark matter searches.