Shock wave in dense gas generated by high power millimeter wave

In this study, MMW shock wave was visualized using shadow graph method. The high power MMW beam generated by lMW-class 170GHz gyrotron was supplied into a shock tube which had rectangular section part. At the rectangular part, visible window is put at both sides. The ignition part is set 15cm far from measurement part to avoid the effect of breakdown ignition at the shock tube. The probe light by He-Ne laser was transmitted through the window and the shadow graph picture was taken by a fast framing camera (NAC´s Ultra-8).