MHD and EMH effects in POS gap opening

Abstract

Summary form only given. Conduction and opening processes of plasma opening switches (POS) are examined with the aid of numerical simulations. In a POS, a plasma initially bridges a small axial region of the transmission line of an inductive energy storage generator. A section of vacuum transmission line then connects the POS region to a load. The plasma initially carries the generator current, allowing no current to flow to the load. Modifications to the plasma or to the current distribution in the plasma eventually open the POS, allowing power to flow to the load. These modifications can occur by a variety of different mechanisms: by plasma deformation and displacement, by magnetic field transport, or by a combination of such effects. Deformation and displacement are carried out by J/spl times/B forces and by electrostatic forces (ion erosion) associated with electron vortices. Magnetic field penetration can occur by electron-magneto-hydrodynamic (EMH) effects or resistive diffusion. Both particle-in-cell (PIC) and MHD codes are used to demonstrate many of these effects. In these simulations, a wide range of plasma densities (n/sub e/=5/spl times/10/sup 12/-5/spl times/10/sup 15/ cm/sup -3/) are examined.