Imaging Spectroscopy of Pellet Clouds in a Helical Plasma

Imaging spectroscopy is a powerful method for the investigation of pellet clouds ablating in high-temperature plasmas which is needed both for the development of pellet ablation models and pellet applications as a diagnostic tool. Spatial distributions of radiation intensities in different spectral intervals are measured by means of the nine-channel imaging polychromator with fairly good spatial, spectral, and temporal resolution. Data are used to derive the spatial distributions of electron density and temperature in the ablated cloud of the polystyrene pellet injected into a large helical device.