Journal article

Publication year: 2021

Journal: Journal of Physics B: Atomic, Molecular and Optical Physics

Volume number: 54

Issue number: 5

ISSN: 0953-4075

eISSN: 1361-6455

Open access status: Green

DOI Link: https://doi.org/10.1088/1361-6455/abd91c

Publisher: IOP Publishing

Abstract: 
Tunable diode laser induced fluorescence (TDLIF) measurements are discussed and quantitatively evaluated for nitrogen admixtures in argon plasma under the influence of a strong magnetic field. TDLIF measurements were used to evaluate light-transport properties in a strongly magnetized optically thick argon/nitrogen plasma under different pressure conditions. Therefore, a coupled system of rate balance equations was constructed to describe laser pumping of individual magnetic sub-levels of 2p(8) state through frequency-separated sub-transitions originating from 1s(4) magnetic sub-levels. The density distribution (alignment) of 2p(8) multiplet was described by balancing laser pumping with losses including radiative decay, transfer of excitation between the neighboring sub-levels in the 2p(8) multiplet driven by neutral collisions (argon and nitrogen) and quenching due to electron and neutral collisions. Resulting 2p(8) magnetic sub-level densities were then used to model polarization dependent fluorescence, considering self-absorption, which could be directly compared with polarization-resolved TDLIF measurements. This enables to estimate the disalignment rate constant for the 2p(8) state due to collisions by molecular nitrogen. A comparison to molecular theory description is given providing satisfactory agreement. The presented measurement method and model can help to describe optical emission of argon and argon-nitrogen admixtures in magnetized conditions and provides a basis for further description of optical emission spectra in magnetized plasmas.

Harvard Citation style: Bergert, R., Isberner, L., Mitic, S. and Thoma, M. (2021) Disalignment rate coefficient of argon 2p₈ due to nitrogen collision, Journal of Physics B: Atomic, Molecular and Optical Physics, 54(5), Article 055701. https://doi.org/10.1088/1361-6455/abd91c

APA Citation style: Bergert, R., Isberner, L., Mitic, S., & Thoma, M. (2021). Disalignment rate coefficient of argon 2p₈ due to nitrogen collision. Journal of Physics B: Atomic, Molecular and Optical Physics. 54(5), Article 055701. https://doi.org/10.1088/1361-6455/abd91c