Light intensity analysis of plasma jet constriction with applied magnetic field

Light intensity analysis was carried out to consider the constriction of plasma jet with the application of a strong magnetic field. Argon was employed as working gas. Plasma jet was generated in a vacuum chamber by a plasma torch and went into a magnet bore. The magnet composed of a pair of superconducting coils imposes a strong axial magnetic field on the jet. The jet between the coils was taken with  a digital single-lens reflex camera through viewing window. The light intensity is determined from the RAW image files of the camera with the software for analyzing the RAW format. The jet constriction with applied magnetic field was evaluated quantitatively on the basis of the obtained results. The distributions of the light intensity were also compared with those of the typical spectral lines from excited argon that were measured at the same time as shooting the images. The results suggest that the light intensity analysis of the RAW image files could be utilized for the quantitative evaluation of the constriction of plasma jet due to the magnetic field.