title: Characterization of argon direct-current glow discharge with a longitudinal electric field applied at ambient air.
abstract: A direct-current-driven plasma jet is developed by applying a longitudinal electric field on the flowing argon at ambient air. This plasma shows a torch shape with its cross-section increased from the anode to the cathode. Comparison with its counterparts indicates that the gas flow plays a key role in variation of the plasma structure and contributes much to enlarging the plasma volume. It is also found that the circular hollow metal base promotes generation of plasma with a high-power volume density in a limited space. The optical emission spectroscopy (OES) diagnosis indicates that the plasma comprises many reactive species, such as OH, O, excited N2, and Ar metastables. Examination of the rotational and vibrational temperature indicates that the plasma is under nonequilibrium condition and the excited species OH(A (2)Σ(+)), O((5)P), and N2(C (3)Πu) are partly generated by energy transfer from argon metastables. The spatially resolved OES of plasma reveals that the negative glow, Faraday dark space, and positive column are distributed across the gas gap. The absence of the anode glow is attributed to the fact that many electrons in the vicinity of the anode follow ions into the positive column due to the ambipolar diffusion in the flowing gas.
authors.affiliation: State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China.
authors.forename: Weiman
authors.initials: W
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China.
authors.forename: Yishan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.affiliation: 1] State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China [2] Research Center of Analytical Instrumentation, Sichuan University, Chengdu 610064, China.
authors.forename: Yixiang
authors.initials: Y
authors.lastname: Duan