Measurement of Stark Profiles of Singly Ionized Nitrogen Lines from a T-Tube Plasma

Abstract

A hot plasma composed of helium and ionized nitrogen was created by reflecting the shock wave produced in an electromagnetic T tube. The plasma temperature was measured by monitoring three nitrogen-ion lines whose intensities are strong functions of temperature. The profiles of various lines emitted in the plasma were obtained by scanning with a monochromator from shot to shot. The half-width of He I 3889 Å was compared with empirically corrected calculations to determine the electron density. Half-widths of various nitrogen-ion lines were measured from the impact-broadened profiles; their shifts were obtained by comparing these profiles with unshifted lines from a pulsed capillary discharge. The results indicate agreement between experiment and recent Stark-broadening calculations within 20%, except for lines originating from the $4f$ level where Debye screening effects are important. No evidence was found for plasma polarization shifts.