Cusp Compression Experiments

Abstract

A shock‐heated plasma of density 3.5 × 10¹⁵ cm⁻³ and temperature 4 × 10⁴ °K is compressed by a rising cusp field which reaches 34 kG between the coils in 15 μsec. Time resolved measurements of electron density and temperature, plasma radius and hole size (at the ring cusp) are described and compared with the predictions of a simple hydrodynamic model in which the primary loss is by classical diffusion across field lines. The agreement between theory and experiment is within a factor of two and strengthens evidence provided by framing pictures that the plasma is stably confined for times of the order 10 μsec, with peak densities and temperatures of 2 × 10¹⁶ cm⁻³ and 16 ×⁶ 10⁴ °K, respectively.