Observations have shown that space is filled with plasma e.g., stellar winds, interstellar medium, intergalactic medium. Around a compact object plasma from ambient medium or surrounding stars forms the accretion disks. These accretion disks drive a part of its matter in the form of a jet. Another important thing is that space is also filled with magnetic field. Astrophysical objects have magnetic field in very broad range e.g., average sun’s magnetic field ∼ 1G, region near to black hole has magnetic field ∼ 10^(3−4) G, white dwarfs have magnetic field ∼ 10^(6−8) G, and neutron stars have magnetic field ∼ 10^(8−12) G. Therefore, plasma (i.e., stellar winds, accretion disks or jets) is embedded in the magnetic field of astrophysical objects. To study the dynamics of the astrophysical flows (stellar wind, jet, and accretion process) around a compact object, it is important to include the effect of the magnetic fields.

In my thesis, we have carried out a detailed study for magnetized astrophysical flows e.g., accretion, winds and jets in magnetohydrodynamics and special relativistic magnetohydrodynamics regime. In astrophysical flows, temperature varies by two to four orders of magnitude. Moreover, the composition of the plasma is not known. We have used variable adiabatic index EoS (CR-EoS). For the first time, we have calculated consistent magnetized accretion solutions on to compact objects with the hard surface such as neutron stars and white dwarfs in Newtonian & pseudo-Newtonian regime with the inclusion of cooling processes like bremsstrahlung and cyclotron emission. We have also studied shocks in magnetized accretion solutions and calculated the total luminosity of solutions which is in good agreement with observations.

To study magnetized outflows, we have investigated the Weber-Davis type winds around compact objects with CR EoS. We have found that terminal velocity and temperature depend on the plasma composition. For the same values of the Bernoulli parameter and the total angular momentum, wind in strong gravity (pseudo-Newtonian) is more accelerated, compared to wind in Newtonian gravity. We continue our outflow study for collimated outflows or jets in special relativistic magnetohydrodynamics with variable adiabatic index EoS. We found that plasma composition mainly affects the velocity and the temperature of the jet, although it appears to have little influence on the streamline of the flow.