Indexed by:期刊论文

Date of Publication:2019-05-01

Journal:IEEE TRANSACTIONS ON PLASMA SCIENCE

Included Journals:EI、SCIE、CPCI-S

Volume:47

Issue:5,SI

Page Number:1909-1916

ISSN No.:0093-3813

Key Words:Argon; cascaded arc plasma; electron density; electron temperature; laser Thomson scattering (LTS); nitrogen

Abstract:The electron density and electron temperature of the recombining argon plasma from a cascaded arc discharge source were measured by the laser Thomson scattering approach. In this paper, a small amount of nitrogen gas was introduced into the argon discharge source. The addition of the nitrogen gas was applied to investigate the change of the plasma parameters in terms of electron density and temperature. The measurements showed that the electron density dropped by 2 orders of magnitude at 10% nitrogen gas addition compared with no nitrogen addition. The dissociative recombination following the charge transfer between atomic ions and nitrogen molecules was responsible for the decrease of electron density. In addition, with the increase of nitrogen gas addition, the measurements indicated that the electron temperature first increased to a maximum and then decreased. This was due to that the superelastic collision between the electrons and the highly excited vibrational nitrogen molecules could heat the electrons leading to the increase of electron temperature while the electron-vibrational energy transfer by electron-nitrogen molecules impact excitation resulted in that electron temperature decreased due to electrons' kinetic energy losing processes.