The lower hybrid drift instability and the modified two stream instability in high density theta pinch environments

Abstract

The lower hybrid drift instability and the modified two stream instability are examined in a parametric environment characteristic of high density theta pinch implosions. A local Vlasov theory with provisions for electromagnetic effects and gradients in density, temperature and magnetic field is used. Under typical experimental conditions the lower hybrid drift instability is dominant. The effects of finite beta on the most rapidly growing modes are destabilizing and primarily manifest through the increased magnetic field gradients associated with increased beta . The theory is applied to experimental profiles of density, temperature and magnetic field to deduce the spatial structure of the instability properties within an implosion sheath.