Study of a high power capillary discharge
Date
1999
Authors
González, Juan José, author
Rocca, Jorge J., advisor
Wilbur, Paul J., committee member
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Abstract
The direct generation by electrical discharges of hot and dense plasma columns with large length-to-diameter ratio is of interest for the development of efficient soft x-ray lasers and has resulted in the generation of coherent radiation at wavelength as short as 46.9 nm. This work presents the first experimental results of a new high power density capillary discharge designed to explore the generation of axially uniform plasma columns for the development of discharge pumped lasers at shorter wavelengths. A high power pulsed power generator based on a three-stage pulse compression scheme was developed. The final stage consist of a water dielectric Blumlein transmission line designed to generate current pulses of up to 225 kA with a 10-90 % rise-time of = 10 ns through the capillary load. Argon plasmas generated in polyacetal and ceramic capillaries were studied by means of time resolved soft x-ray pinhole camera images and time resolved XUV spectroscopy. The pinhole images show that the current pulse rapidly compresses the plasma to form a column with a soft x-ray emitting region with a diameter of ≈ 250 μm. Spectra in the 18-23 nm region are observed to be dominated by an ArXV line. The experimental data obtain is in agreement with model computations that suggest these discharge conditions should generate plasma columns of ~ 200-300 μm in diameter with electron temperatures > 250 eV and densities of 1-2x10 20 cm-3.
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Subject
Laser plasmas
Plasma generators
X-ray lasers
Pulse generators