Retrieval of refractive index distribution in an anode layer from Fourier image of probe laser beam

Quality of an intense ion beam generated in the ion diode sufficiently depends on characteristics of the anode plasma. One of the ways to study the anode layer is a refractive index gradient diagnostics based on the record of deflection of a collimated laser beam. To retrieve a refractive index distribution across the layer by such a technique one needs to perform a number of measurements at different distances of the laser beam from the anode surface