It would appear that if the source of luminosity is in motion in the ring electrodeless discharge, that there should be a broadening of the spectral lines when viewed in the line of motion.
Proceedings of the Iowa Academy of Science
©1911 Iowa Academy of Science, Inc.
Almy, Frank F.
"The Doppler Effect in Electrodless Discharge,"
Proceedings of the Iowa Academy of Science, 18(1), 123-123.
Available at: https://scholarworks.uni.edu/pias/vol18/iss1/26