Bonn 2000 – scientific programme

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P: Plasmaphysik

P 21: Dichte Plasmen (Poster)

P 21.10: Poster

Thursday, April 6, 2000, 17:00–19:30, Aula

Investigation of x-ray lasing in a capillary discharge — •S. Ellwi, L. Juschkin, and H.-J. Kunze — Institut für Experimentalphysik V, Ruhr-Universität, 44780 Bochum, Germany

Using the method of ablative capillary discharge from a capillary made of Polyacetal we observed an intense spike of the Balmer-α of Cvi at 18.22 nm during the second half-cycle of the discharge. Different wavelengths were scanned and we have seen no spike with the exception of the one mentioned above. The spikes were tentatively identified as Amplified Spontaneous Emission (ASE), and enhancements were derived for capillaries of 15, 20, 25 and 30 mm. The amplitude of the spike increased with increasing the length of the capillary and decreasing the inner diameter of the capillary. Time integrated measurements were recorded using a flat field and grazing incidence spectrometers. A photomultiplier was used to record the time history measurement of the spike. The time duration of the spike was about 2 ns. We implemented a new method to enhance these spikes by using a straight capillary but with a waved structure imprinted inside. The result was encouraging and the spikes were enhanced.

We explained the ASE as a result of charge exchange between plasma ions produced by an MHD instability.