Characterization by laser-induced photodetachment of anions formed during dust particle growth in a magnetically confined very low-pressure argon–acetylene plasma. (11th July 2017)

• Record Type: Journal Article
• Authors: Al Makdessi, Georges; Hamdan, Ahmad; Margot, Joëlle; Clergereaux, Richard
• Is Part Of: Plasma sources science & technology. Volume 26:Number 8(2017:Aug.)
• Publication Date: 2017-07-11
• Subjects: laser photodetachment -- magnetized plasma -- acetylene -- negative ions -- carbon nanoparticles; Plasma (Ionized gases) -- Periodicals; 530.44
• DOI: 10.1088/1361-6595/aa7806
• Languages: English
• ISSNs: 0963-0252

Abstract

Abstract: Anions in low-pressure magnetically confined Ar–C2 H2 plasmas were investigated using the laser-induced photodetachment technique. In particular, the influence of the magnetic field ( B ) was studied. We observed that the density of negatively-charged species n – increases with B and slightly decreases when the C2 H2 percentage grows. These phenomena are the result of changes in the plasma kinetics. We also observed that n – decreases as the pressure increases from 2 to 10 mTorr due to the corresponding rise of the collision frequency, which leads to enhanced losses of the negatively-charged species. In parallel, the photodetachment cross-section was deduced from the energy dependence of the photodetachment signal and was found to be close to that of C2 H − anions, which indicates that these anions are likely to dominate the negative ion population.