Accession Number : ADA014737

Title :   Investigation of the Stability of Laser Discharges.

Descriptive Note : Final rept. 22 Jan 73-28 Feb 75,


Personal Author(s) : Bullis,R. H. ; Nighan,W. L. ; Wiegand,W. J.

Report Date : JUN 1975

Pagination or Media Count : 48

Abstract : Calculations indicate that thermal and/or vibrational instabilities will occur for most discharge conditions of importance in high power, cw carbon dioxide convection lasers. Computed characteristic growth times for these modes are typically on the order of 1 msec. The experimental investigations described herein have verified that it is the growth of disturbances in gas translational or vibrational temperature which is responsible for the discharge constriction observed in carbon dioxide laser plasmas. Moreover, because of the characteristic msec instability growth times, convection of the unstable portions of the medium out of the plasma region can effectively stabilize the discharge. The beneficial aspects of having homogeneous gas flow conditions and uniform electrical power deposition are suggested by the theory. Experimental results confirm that such plasma and fluid dynamic uniformity permits operation at increased electric power inputs and higher pressures. Extension of these results to CO lasers and electron-beam sustained plasmas is discussed.

Descriptors :   *Carbon dioxide lasers, *Carbon monoxide lasers, *Gas discharges, Plasmas(Physics), Gas ionization, Coherent radiation, Electric discharges, Electron beams, Stability, Gas dynamics, Collisions

Subject Categories : Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE