Beat heating in plasmas using COb2s lasers

An experiment using the 10.28 ym and 9.56 ym radiation from a high power CO2 laser and a preionized helium plasma was conducted to investigate anti-parallel beam beat heating. The helium plasma is heated by a focused single, double pass, laser beam with two frequency components. The temperature increase is compared with that obtained using a single frequency laser. A small amount of additional heating is observed with the double frequency laser beam 22 -3 at a spatially average plasma density of 5.3x10 m . However, this additional heating is not as strong as originally expected. The results are explained by the detuning of the beat heating process at the interaction zone due to particle losses.