CC BY
4
ALT'23
The 30th International Conference on Advanced Laser Technologies
LS-P-12
Optimization of energy costs for the generation of metastable argon atoms in a repetitively pulsed discharge in an Ar-He mixture
M. Zagidullin1,2, P. Mikheyev1, A. Dvornikov2
1- P.N. Lebedev Physical Institute, Samara branch, 221 Novo-Sadovaya st. Samara, 443011, Russia 2- Samara National Research University, 34, Moskovskoye shosse, Samara, 443086, Russia
zagidullin_marsel@rambler. ru
In this work, the specific heat W, released in a nanosecond repetitively pulsed discharge (NRPD) in an Ar-He = 1:99 mixture at atmospheric pressure, when the produced number density of argon metastable atoms is 1013 cm-3 and water is present as the impurity, was calculated with the help of 0-D numerical model. The dependence of W on the reduced electric field E/N and repetition rate of applied discharge voltage pulses with triangular shape and 80 ns duration at their base was obtained for different water content. A repetitively pulsed discharge in a mixture of inert gases at an atmospheric pressure with a pulse duration from a few to hundreds of nanoseconds with a high pulse repetition rate (>100 kHz) is an effective way to produce a quasi-continuous weakly ionized homogeneous plasma, which is of interest for a number of applications [1,2]. Minimization of energy costs for the production of the required number density of metastable atoms of a noble gas plays an important role for scaling of the discharge volume and facilitating discharge stability. With a large pulse duty cycle and a repetition rate of ~ 100 kHz, the kinetics during the afterglow stage plays an essential role in the NRPD, forming a decaying plasma where the next discharge pulse occurs. The model includes 10 electron impact processes and 31 plasma chemical processes during discharge pulse and afterglow. Initial condition was set as a large enough homogeneous ionization. Stable periodical solution appeared after 100-200 discharge pulses. For the triangular applied discharge voltage, the averaged over the discharge period number density [Ar(s5)] is a function of three parameters: water content, repetition rate of the discharge pulses f and amplitude of E/N.
Figure 1a represents the dependence of pulse repetition rate f on E/N for different water content, when [Ar(s5)] = 1013 cm-3. Figure 1b represents the dependencies of W on E/N for these conditions, showing that there are pairs of (f, E/N), when these dependencies exhibit minima. Evidently, there is a strong dependence of positions of these minima on the water content.
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Fig. 1. Dependence of: a) - required for production of [Ar(s5)] = 1013 cm-3 pulse repetition rate f on E/N, b) - heat release W on E/N for the
repetition rates according to Fig. 1 a).
This work was supported by RSF grant № 23-22-10013, https://rscf.ru/project/23-22-10013/.
[1] J. Han, M. Heaven, P. Moran, A. Pitz, E. Guild, C. Sanderson, B. Hokr, Demonstration of a CW diode-pumped Ar metastable laser operating at 4 W, Optics Letters, vol.42, pp. 4627-4630, (2017).
[2] P. Mikheyev, A. Chernyshov, M. Svistun, N. Ufimtsev, O. Kartamysheva, M. Heaven, V. N. Azyazov, Transversely optically pumped Ar: He laser with a pulsed-periodic discharge, Optics express, vol. 27, pp. 38759-38767, (2019).
