High Brightness and Density Plasma Source by Novel Capsule Theta Pinch

Theta pinch is a classic magnetic confinement plasma configuration. A novel capsule theta pinch (CAT) device is designed to study plasma changes as an application for pulsed high density ion source and high brightness light source. The capsule-shaped vacuum vessel consists of two hemispherical ends and a middle tubular cylinder made of 5.0 mm quartz glass. The vessel’s volume is 24.7 L, wound with a 4 -turn copper coil connected in series. The pulsed power supply, which generates large current in the coil, consists a 50F film pulsed capacitor bank and a ignitron as the high voltage/large current switch. The working pressure is 1 100 Pa with Argon as the discharge gas. The maximum current in the external coil reaches 35 kA with the maximum magnetic field of 1.6 T at the edge of inner vessel. The electron density evolutions are measured by the optical fiber interferometer (OFI) with high temporal and spatial precision. The radial profiles of the electron density are tomographically reconstructed using the multi-channel OFI. The maximum electron density reaches the level of 10
²³
m
^-3
at the center of the vessel. The brightness of plasma light emitting is diagnosed by the calibrated free-space Si based photodetector, and the maximum instantaneous luminous power reaches 15 kW. The plasma luminescent spectrum ranges from 300 to 900 nm with 14 mW/cm
²
/nm irradiance at 410 nm. The dynamics of CAT discharges are further researched to achieve higher density and brighter source. The evolutions of magnetic field profile are obtained using radially moveable 3D magnetic field pick-up probes. And the pinching process is recorded by a visible-light and high-speed camera at a frame rate beyond 200 kfps. The detailed radial implosion is analyzed by comparing profiles with the photographs of plasmas evolution. The preliminary experimental results will be shown in the poster.