Dynamical Analysis Of Jeans Instability For Self-gravitational Systems Based On EiBI Gravity Theory

Jeans instability is one of the most vital mechanisms to explain the gravitational formation of structures and their evolution,which has been widely studied in the field of astrophysics,plasma,and complex fluid community.However,more and more challenges to the conventional Jeans theory have emerged as the development of modern astronomy and the observation data involving the statistical description become increasingly more accurate.Therefore,it is necessary to modify the conventional Jeans instability theory,in which the application of different gravity theory,thermodynamic statistics and geometric configuration,are the current research hot topics.Among the many theories of modified gravitation,the famous Eddington-inspired-Born-Infeld(EiBI)gravity has received extensive attention and research because it avoids the initial singularity of the universe.Under the framework of spherically symmetric geometry,the Jeans instabilities for self-gravitational systems have been investigated in the context of EiBI gravity based on plasma hydrodynamics theory.The results show that,for ideal fluid,the EiBI gravity parameter acts as the instability factor of the system and promotes the collapse of the system under the negative EiBI gravity background.In the context of positive EiBI gravity,EiBI gravity acts as a stabilizing factor to strengthen the stability of the system.In addition,whether EiBI gravity is positive or negative,the stability of the system increases with the increase of radial distance,which always plays a stabilizing role on the system.Furthermore,considering the viscoelastic effect of astrophysical fluids,the Jeans instability of viscoelastic fluids is re-studied in the context of EiBI gravity.The results show that positive EiBI gravitational parameters and effective generalized fluid viscosity can effectively suppress the collapse of the matter system,while negative EiBI parameters and viscoelastic relaxation time can aggravate the instability of the self-gravitational system.This result is helpful to explore the role of EiBI theory in viscoelastic compact media,and has important reference value for further study of neutron stars,white dwarfs and other compact astrophysical fluids.Finally,based on the framework of plasma kinetic theory,the Jeans instability of self-gravitation system is investigated under the perturbation with orbital angular momentum(OAM).The numerical results indicate that the growth rate of Jeans instability is enhanced with the OAM parameter increased,while the critical wave number is consistent with the classical Jeans critical value.In addition,the effect of OAM on the instability of the system does not change with EiBI gravity.