Three-dimensional MHD modeling of railgun plasma armature with the CE/SE method

Three-dimensional (3-D) numerical simulations have been carried out taking into account the magnetohydrodynamics (MHD) effect of the railgun plasma armature. The 3-D space-time conservation element and solution element (CE/SE) method is derived for solving the coupled Navier-Stokes equations and Maxwell equations. The results show that a steeper gradient of the magnetic field and pressure that appears along the direction of the rail can be observed. The temperature distribution is affected by the boundary conditions for the radiative heat flux, with the maximum temperature appearing in the center near the base of the projectile. Circulation patterns of velocity that are evident in both the rail-to-rail plane and the insulator-to-insulator plane result from the convection and unbalanced force between the Lorentz force and pressure gradient. The periodical variation of the temperature and acceleration is obvious until a new steady state is achieved. This model can efficiently evaluate the dynamics of the plasma motion, and provide a basis on understanding the much more complex physical phenomena.