TY - JOUR

T1 - Superposition of low-pressure DBD and RF induction discharge for spectroscopic study of dissociative recombination in decaying plasma

AU - Ivanov, Vladimir

PY - 2020/4

Y1 - 2020/4

N2 - The aim of the work was to find the optimal way to set up an experiment for spectroscopic study of the dissociative recombination of molecular ions with electrons in low electron density plasma at low gas pressure. In such an experiment, the influence of inelastic atom- atom collisions on the distribution of the DR flux over the excited atomic levels can be excluded. The first results of an experiment on combining a low-frequency barrier discharge (DBD) in neon at a pressure of less than 1 Torr with a pulsed radio-frequency (RF) induction discharge are presented. To create the plasma, we used DBD in a cylindrical glass tube with an inner diameter of 3.9 cm, which forms the spatial distribution of electron density with a minimum on the axis of the tube. The evolution of such a spatial distribution due to ambipolar diffusion in the initial stage of plasma decay provides an influx of charged particles to the center of the discharge tube, which increases the afterglow duration and helps to overcome the difficulties of detecting weak plasma radiation. The specific features of the DBD also appeared in the ionic composition of the plasma, which contained, in addition to Ne + and Ne2 +, tht Ne ++ ions, whose recombination with electrons significantly enriched the afterglow spectrum in the short-wavelength region. An RF discharge was used for pulsed heating of electrons in the afterglow. It is shown that, in accordance with the ionic composition of the plasma, the radiation of a decaying plasma is presented by three groups of spectral lines with characteristic time behavior and the electron temperature dependence. The advantages of the proposed approach for studying the mechanism of dissociative recombination are discussed.

AB - The aim of the work was to find the optimal way to set up an experiment for spectroscopic study of the dissociative recombination of molecular ions with electrons in low electron density plasma at low gas pressure. In such an experiment, the influence of inelastic atom- atom collisions on the distribution of the DR flux over the excited atomic levels can be excluded. The first results of an experiment on combining a low-frequency barrier discharge (DBD) in neon at a pressure of less than 1 Torr with a pulsed radio-frequency (RF) induction discharge are presented. To create the plasma, we used DBD in a cylindrical glass tube with an inner diameter of 3.9 cm, which forms the spatial distribution of electron density with a minimum on the axis of the tube. The evolution of such a spatial distribution due to ambipolar diffusion in the initial stage of plasma decay provides an influx of charged particles to the center of the discharge tube, which increases the afterglow duration and helps to overcome the difficulties of detecting weak plasma radiation. The specific features of the DBD also appeared in the ionic composition of the plasma, which contained, in addition to Ne + and Ne2 +, tht Ne ++ ions, whose recombination with electrons significantly enriched the afterglow spectrum in the short-wavelength region. An RF discharge was used for pulsed heating of electrons in the afterglow. It is shown that, in accordance with the ionic composition of the plasma, the radiation of a decaying plasma is presented by three groups of spectral lines with characteristic time behavior and the electron temperature dependence. The advantages of the proposed approach for studying the mechanism of dissociative recombination are discussed.

KW - Collisional-radiative recombination

KW - Dielectric-barrier discharge

KW - Dissociative recombination

KW - Low-pressure plasma

KW - Molecular ions

KW - Optical emission spectroscopy

KW - Radio-frequency discharge

KW - ION-CONVERSION PROCESSES

KW - low-pressure plasma

KW - optical emission spectroscopy

KW - dielectric-barrier discharge

KW - collisional-radiative recombination

KW - MOLECULAR-IONS

KW - AFTERGLOW

KW - TOTAL RATE COEFFICIENT

KW - molecular ions

KW - ELECTRON-TEMPERATURE DEPENDENCE

KW - radio-frequency discharge

KW - NEON

KW - EXCITED-STATE PRODUCTION

KW - ATOMS

KW - BARRIER DISCHARGE

KW - HELIUM

KW - dissociative recombination

UR - https://iopscience.iop.org/article/10.1088/1361-6595/ab7f4c

UR - http://www.scopus.com/inward/record.url?scp=85085243273&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/ec656b40-4e2d-3761-b908-17a76ba2e2a6/

U2 - 10.1088/1361-6595/ab7f4c

DO - 10.1088/1361-6595/ab7f4c

M3 - Article

VL - 29

SP - 045022

JO - Plasma Sources Science and Technology

JF - Plasma Sources Science and Technology

SN - 0963-0252

IS - 4

M1 - 045022

ER -