MOIRE DEFLECTOMETRY DIAGNOSTIC FOR TRANSIENT PLASMA, USING A MULTIPULSE N-2 LASER

We have designed a multipulse laser system to measure nanosecond time scale, plasma-density gradients by moire deflectometry. The complete s ystem consists of four, transverse-excited, atmospheric pressure (TEA) N-2 laser oscillators and two low-pressure N-2 laser amplifiers; two oscillator pulses are injected into a single amplifier. The amplified pulses are less than 1 ns in duration, with a variable, interpulse tim e of 4-10 ns. As described here, two TEA oscillators and a single ampl ifier were used to image air-density gradients in an expanding, air-sh ock wave produced by a spark discharge. (C) 1996 American Institute of Physics.