Laser-produced plasma bubble.

In the aftermath of a plasma in atmospheric density H2 produced by a 6 ns, 600 mJ, 1064 nm, Nd:YAG laser pulse, a bubble develops behind the shock front. Within 2 micros the shock detaches from it, but the bubble persists for 100 micros before it is clearly turbulent. While initially spheroidal in appearance with a diameter of about 0.6 cm, after 16 micros the enveloping cold gas penetrates the bubble along the axial channel left by the laser. This results in a distorted torus with a protrusion that moves slowly toward the laser. The images show that the gas processed by the laser-plasma shock front is isolated from the surrounding unprocessed gas until mixed by this flow.