Abstract
Time dependencies of the electrical resistance and electron density evolution in the discharge in a tube, with nitrogen at different pressures, with a diameter of 9.2mm and a length of 10cm were studied. A current pulse with an amplitude of 500A and duration of 10μs has created the discharge in the tube. Instantaneous electron densities are estimated from the interference pattern in Mach–Zehnder interferometer using femtosecond Ti: sapphire laser beam. Laboratory results are compared with results of computer modelling by MHD computer codes NPINCH and ZSTAR. Time development of the discharge resistance according to experiment is measured and evaluated. Minimum measurable value of the electron density in the experiment is determined as 2×1015cm−3.
Highlights
The basic subject of our interest is the temporal development of plasma excited by an electric discharge in a tube filled with nitrogen, in order to create conditions suitable for recombination excitation of a laser at quantum transitions of hydrogen-like nitrogen [1]
Using the computer modelling method, we have shown that the required conditions can be set in a pinching discharge in a non-ablative capillary with a diameter of 3 mm filled with nitrogen to the pressure of 500 Pa excited by a current pulse with amplitude 50 kA and duration 80 ns
We assume that to suppress the effect of ablation on the dynamics of plasma heating, the capillary diameter, and the current pulse shape should be modified, or additional plasma heating with a laser beam should be applied [7]
Summary
The basic subject of our interest is the temporal development of plasma excited by an electric discharge in a tube filled with nitrogen, in order to create conditions suitable for recombination excitation of a laser at quantum transitions of hydrogen-like nitrogen [1]. Using the computer modelling method, we have shown that the required conditions can be set in a pinching discharge in a non-ablative capillary with a diameter of 3 mm filled with nitrogen to the pressure of 500 Pa excited by a current pulse with amplitude 50 kA and duration 80 ns. We assume that to suppress the effect of ablation on the dynamics of plasma heating, the capillary diameter, and the current pulse shape should be modified, or additional plasma heating with a laser beam should be applied [7]. The second pulse (“pedestal”) should be high and fast enough to create a magnetic pressure sufficient to force the plasma to detach from the wall, but not too high in order to keep the current below the tube wall ablation threshold. We focus on the first (pre-ionization) stage and we present a comparison of laboratory experiments and computer simulations of these experiments aimed at determining the spatial distribution of electron density and temperature together with resistance of the plasma-discharge column for slow pre-ionization discharge
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
