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You can download two video clips showing LIBS plasma in air. Both clips were taken simultaneously.  "LIBS_Plasma.mov" is a close-up of the plasma produced by the prototype ChemCam Mast Unit at a distance of 5 m. The sample was moved a distance of 50 cm along a track, showing that the plasma produced by only the 15 mJ laser (no amplifier) was strong enough to be insensitive to focal distance. The distance between the camera and the sample was kept constant while the sample was moved.

"LIBS_Plasma_Video_Set-Up.avi" shows how the first clip was made. It shows the sample and the camera used for the first video being moved along the track. The 15 fps rate misses a few of the laser pulses. Comparison with the close-up clip shows this is an artifact of the camera. Note that the apparent wandering of the plasma position on the sample seen in the close-up clip is due to the motion of the sample. There is no positional instability of the laser relative to the spark size.

In a Martian atmosphere the size and brightness of the visible plasma is greater than in the terrestrial atmosphere, as the lower pressure allows greater expansion of the emitting plasma and reduced self-shielding of the plasma results in greater sample ablation rates (Knight et al., 1999).

LIBS_Plasma.mov requires Quicktime to play, downloadable free from Apple.com.
LIBS_Plasma_Video_Set-Up.avi requires Real Player or a similar Windows video player.

And now, the videos: