Effect of Inhomogeneous Thermal Pressure on Velocity of Cylindrical Magnetohydrodynamic Velocity: A Simulation Study

The effect of non-uniform plasma pressure gradient on the cylindrical magneto-hydrodynamic (MHD) velocity was semi-analytically calculated by numerically solving the MHD equations. The calculated results show that the pressure gradient has a major impact on the axial and azimuthal velocities, but a minor impact on the radial velocity and on the evolution of the axial and azimuthal velocities. To be specific, the non-uniform pressure results in both the positive and negative azimuthal and axial velocities which have a quasi-symmetric distribution and multi extremums, and explains the possible mechanism responsible for the MHD instability; in contrast, a uniform plasma pressure produces only negative azimuthal and axial velocities. All the velocities are reduced to zero on the plasma wall, simply because of the obstruction of the plasma wall to the magnetic fluid.