Two novel fully decoupled schemes for the two-phase MHD system with exactly divergence-free magnetic field

In this paper, we propose a two-phase magnetohydrodynamics (MHD) system based on a magnetic potential formulation in 3D case. This model ensures exactly divergence-free approximation of the magnetic field by introducing magnetic potential A and defining magnetic field B = curl A. Then, we give two completely decoupled, first-order, linear and energy stable schemes, and strictly derive the unconditional energy stability of both schemes under time discretization. Finally, several numerical examples demonstrate the stability and effectiveness for our schemes.