Investigating Hydrogen Plasma Dynamics Via Two-Color Optical Diagnostics

The Caltech MHD Plasma Jet Experiment exhibits a kink-driven Rayleigh-Taylor instability (RTI) that generates localized bursts of EUV and X-Ray radiation. One possible source of these radiation bursts is the formation of a double-layer at the RTI location. Using a specially constructed two color image-splitter, the RTI in a hydrogen plasma jet will be investigated to measure spatial and temporal temperature profiles. The diagnostic tool is designed to create two separate monochromatic images at H_α and H_β wavelengths captured side by side on a single frame taken by an Imacon 200 high speed camera. The operating principle of the diagnostic tool will be discussed and a description of the post-processing will be given. Movies of plasma temperature will be generated from the ratio of the intensity of the H_α and H_β images. These movies are expected to reveal new dynamics associated with the RTI. The correlation between local temperature change and observed dimming will also be examined. These measurements should provide insight into mechanisms by which the plasma locally changes from cold and collisional to hot and collisionless.

Supported by NSF Award No. 2105492.