Feasibility study of a shadowgraphy plasma diagnostic using a high-speed framing camera

An Imacon 675 electro-optical camera operating as fast as 6 x 108 frames/sec was used to record ten consecutive shadowgrams of transient plasma interactions. The resolution of the camera system at 6 x 108 frames/sec is 4 line pairs/mm perpendicular to the time-sweep direction and 2 line pairs/mm parallel to the time-sweep direction. At 5x optical magnification this corresponds to a resolution of 50 μm x 100 μm in the object plane, with a 2 mm x 1 mm field of view. The probe laser is a 100 mW cw argon-ion laser. This probe laser power is marginal in that it is just above the system recording threshold and is only slightly brighter than the plasma emission. A more intense probe laser would improve system performance considerably and may allow this technique to be a useful plasma diagnostic tool