Spectroscopic Characteristics of Supersonically Expanding Nitrogen Arc-Jet Plume—Strong Atomic Lines and Weak Molecular Band Spectra

We generate recombining nitrogen plasma plume by expansion of nitrogen arc into lower pressure vessel with a weak longitudinal magnetic field in a steady state. Spectroscopic observation reveals that the plasma has almost no component of molecular band spectra. Meanwhile, atomic nitrogen lines are observed with considerable intensity. The reason for this spectroscopic peculiarity is discussed in terms of chemical thermodynamics of the nitrogen thermal arc plasma and of nonequilibrium characteristics.