| Abstract : | The time-dependent fluid equations can describe a wide range of astrophysical phenomena like accretion, winds, and jets. The physics of these flows around compact objects are interesting because of their strong gravity and high magnetic field (like in the case of neutron stars). These equations are highly non-linear and analytical solutions are prohibitive in most cases. Several numerical methods to solve fluid equations have been developed so far. Most of the simulation codes for fluid flow around compact objects are based on the fixed adiabatic index equation, which can be a poor approximation in astrophysical scenarios, where the flows are often transonic and trans-relativistic. Also, this equation of state does not take care of the composition of the plasma. Hence, implementing an equation of state in simulation codes, which governs the thermodynamics of multispecies plasma, remains an open question. To address this problem, we have developed a new MHD simulation code with the equation of state given by Chattopadhyay & Ryu (2009), which can account for the thermodynamics of the plasma which is a mixture of electrons, protons, and positrons. Using this code, we show that the plasma composition significantly affects the dynamics of the flow. |
