Plasma Laboratory - Weizmann Institute of Science

Z-pinch 2D interferometry results

Inferring the 3D density distribution of the gas requires treating each pixel of the interferograms obtained as a single chordal interferometer measurement and performing Abel inversion. The density distribution derived is absolute, providing the relation between the pressure set at the valve inlet and the gas density.

However, useful information can be extracted with no analysis, such as the sharpness of the density gradient between the jet outer shell and the vacuum, and the collimation of the flow. Fig. ‎1 shows interferograms obtained using two types of nozzles. It is evident that while the initial radius of the jet in Fig. ‎1(a) is smaller, using a converging-diverging nozzle produces a more collimated flow.

Fig. ‎1: Interferograms obtained using a 0.8 mm bore in place of the nozzle (a) and a conveging-diverging nozzle (b).

Both interferograms were taken with N2 gas at steady-state flow, with a pressure setting of 100 bar and a 1 μs exposure time. Direction of flow is top to bottom.

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Modified on: 2010-05-23