摘要: Over the past fifteen years it has become increasingly clear that Hall magnetohydrodynamics plays a crucial role in many space and laboratory plasma processes: magnetic reconnection, sub-Alfenic expansions, opening switches to name few. is important for dynamics on length scales less than ion inertial scale but greater electron length. On these motions are decoupled; electrons remain frozen field ions not. In this paper we provide basic overview of magnetodydrodynamics with an emphasis numerical methods. We also several concrete examples dynamics: whistler waves, drift switch dynamics, three dimensional reconnection.