CHARACTERIZATION AND USE OF AN OPTICAL-FIBER INTERFEROMETER FOR MEASUREMENT OF THE ELECTRIC WIND

An optical fiber interferometer of the Mach-Zehnder type has proved to be a convenient and accurate method for measuring the electric wind i n the active region of a corona discharge. The technique relies on the cooling effect of the wind on a small heated region of one arm of the interferometer, which has been remotely heated with an infrared CO2 l aser beam. Wind speeds of up to 5.5 m s(-1) have been measured near th e generation region, and by the use of a mesh electrode, the wind has been detected on the axis up to 0.5 m away from the gap. A number of c haracterization experiments that show the interferometer to be a usefu l diagnostic tool in the quantitative analysis of the CO2 laser beam h ave also been carried out, and good agreement between experimental res ults and theoretical calculations based on a simple heat-power balance equation for the fiber exists.