Numerical and experimental study of supersonically expanding argon plasma using a micrometer hollow cathode discharge

Journal of Applied Physics, vol. 135

Abstract

Pulsed discharge nozzles (PDNs) have been successfully used for decades to produce rotationally cold (Trot ∼ 20 K) radicals and ions of astrophysical interest and to characterize these species spectroscopically. In this work, an evolution of the PDN, the piezostack pulsed discharge nozzle (P2DN), is used for the first time to investigate the characteristics of the still poorly understood supersonic plasma expansion. The P2DN allows for a better control of the reservoir pressure of which an accurate measurement is required to characterize the plasma expansion. This new source, thus, gives the opportunity to further optimize the plasma conditions and extend its use to new target species. The spatial distribution of an argon plasma and the effect of the supersonic flow for different pressures are studied by combining a two-dimensional extended fluid model (extFM) and a direct simulation Monte Carlo (DSMC) method. The combined simulation is validated with experimental results obtained through emission spectroscopy associated with a group-code collisional-radiative model to retrieve the plasma parameters. The validated numerical approach (DSMC-extFM) allows for an accurate characterization of the plasma structure in our typical experimental conditions (a reservoir pressure ranging from 90 to 905 mbar). Thus, this simulation will be used in future studies to improve the plasma conditions to favor the synthesis of (transient) hydrocarbon species as found in space, by seeding the argon gas with a suitable precursor, such as acetylene.

Authors 5

1. Y. T. Gu Aachen Laboratory for Astrophysics, Leiden Observatory

   Leiden University · Leiden Observatory · Xi'an Jiaotong University

   Affiliation as printed

   Key Laboratory of Physical Electronics and Devices of Ministry of Education, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University 1 , Xi’an 710049, China

   Laboratory for Astrophysics, Leiden Observatory, Leiden University 2 , 9513, RA Leiden 2300, The Netherlands

2. Nicolas Suas-David Aachen Laboratory for Astrophysics, Leiden Observatory

   Leiden University · Centre National de la Recherche Scientifique · Institut de Physique de Rennes · Leiden Observatory · Université de Rennes

   Affiliation as printed

   Institut de Physique de Rennes—UMR 6251, Univ Rennes, CNRS, 3 Rennes F-35000, France

   Laboratory for Astrophysics, Leiden Observatory, Leiden University 2 , 9513, RA Leiden 2300, The Netherlands

3. Jordy Bouwman Aachen Laboratory for Astrophysics, Leiden Observatory

   Leiden University · University of Colorado Boulder · University of Colorado System · Laboratory for Atmospheric and Space Physics · Leiden Observatory · Institute for Modeling Plasma, Atmospheres and Cosmic Dust

   Affiliation as printed

   Department of Chemistry, University of Colorado 5 , Boulder, Colorado 80309, USA

   Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT), University of Colorado 6 , Boulder, Colorado 80303, USA

   Laboratory for Astrophysics, Leiden Observatory, Leiden University 2 , 9513, RA Leiden 2300, The Netherlands

   Laboratory for Atmospheric and Space Physics, University of Colorado 4 , Boulder, Colorado 80303, USA

4. Yongdong Li

   Xi'an Jiaotong University

   Affiliation as printed

   Key Laboratory of Physical Electronics and Devices of Ministry of Education, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University 1 , Xi’an 710049, China

5. H. Linnartz Aachen Laboratory for Astrophysics, Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Laboratory for Astrophysics, Leiden Observatory, Leiden University 2 , 9513, RA Leiden 2300, The Netherlands