Contributed Talk - Splinter Compact

Thursday, 14 September 2023, 17:35   (H 2036)

Towards a Physical Understanding of Plasma Dynamics in the Vicinity of Compact Objects

Mohamad Shalaby
Leibniz Institute for Astrophysics Potsdam

Plasmas near compact objects are characterized by a large magnetic energy density compared to both thermal and kinetic energy densities. For example, near the M87 black hole, the estimated magnetic energy density is more than two orders of magnitude larger than the estimated thermal energy density of emitting electrons. The estimated number densities for these plasmas place the mean free path on a much larger scale compared to all kinetic plasma scales, such as plasma skin-depth and Larmor radius. Therefore, magnetohydrodynamics (MHD) is inadequate to characterize the dynamics of these plasmas. In this talk, I discuss recent efforts to elaborate on the departure of collisionless shocks from behaviors predicted by MHD equations, for both electron-positron and electron-ion shocks. Moreover, I discuss potential ways to incorporate realistic kinetic plasma dynamics in these regimes within MHD models.