Date of Award


Document Type


Degree Name

Master of Science


Department of Engineering Physics

First Advisor

William Bailey, PhD

Second Advisor

Charles DeJoseph, PhD [Wright Laboratory, AFRL]


Recently, Hong and Miller used Fourier Transform Emission (FTE) spectroscopy to determine the N2+ mobility in helium by relating the observed Doppler shift of the N2+ (B-X) transition to the measured electric field in the discharge as determined by probes. In order to establish the technique in-house, this effort duplicated that experiment and investigated the sensitivity and utility of the method. Doppler shift measurements in this experiment disagreed significantly with those reported by Hong and Miller. Attempts to reduce the data (and thus determine the mobility) using a model developed by Hong and Miller were unsuccessful. The model did not qualitatively or quantitatively describe the Doppler shifts observed in this work. At this time, an explanation of the differences between the two experiments is not known. Possibilities include effects of striations on the Doppler shift measurements, competition between one- and two-step excitation of the N2+ (B-X) state, and failure to interpret the Hong and Miller model correctly. Subsequent attempts to model Hong and Miller's own data (taken from their figures) yielded mobility parameters which disagreed with their published results.

AFIT Designator


DTIC Accession Number



Plain-text title form: Measurement of N2+ Mobility in He via Fourier Transform Emission Spectroscopy