Self-Gravitating Plasma

In 2012, I studied the Jeans Instability in f(R)-gravity in the Newtonian limit of the theory following the classical procedure. I obtained a new dispersion relation that led to a new Jeans length, and I also pointed out that the Newtonian value is an upper limit for the Jean mass when the correction to the Lagrangian. In 2017, the same approach has been used to analyze the stability of self-gravitating systems in Eddington-inspired Born–Infield gravity. Results indicate that the dynamics of self-gravitating astrophysical systems can be fully addressed in both theories, f(R)-gravity and Eddington-inspired Born–Infeld gravity. The latter modifies the Jeans instability in high densities environments, while its effects become negligible in star formation regions [1,2]. Afterwards, local perturbations in axisymmetric systems have been considered to compute the Toomre's parameter in Eddington-inspired Born–Infeld gravity. EiBI with positive χ, which is the only free parameter, substantially can suppress the local fragmentation and has stabilizing effects against axisymmetric perturbations. More specifically, we show that only an annulus remains unstable on the surface of the disc [3].

Bibliography

1. Capozziello S., De Laurentis M., De Martino I., Formisano M., Odintsov S.D., ’Jeans analysis of self-gravitating systems in f (R)-gravity’, 2012, Phys. Rev. D, 85, 044022.

2. I. De Martino, A. Capolupo, ’Kinetic theory of Jean Instability in Eddington-inspired Born-Infield gravity’, 2017, Eur. Phys. J. C, 2017, 77, 715

3. Mahmood Roshan, Ali Kazemi, Ivan De Martino, ’Local fragmentation of thin disks in Eddington-inspired Gravity.’, 2018, Mon. Not. R. Astron. Soc., 479, 1287-1296