Cathode fall thickness of abnormal glow discharges between parallel-plane electrodes in different radii at low pressure

Journal Article · Sun Feb 15 04:00:00 EST 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4907660· OSTI ID:22408142

Fu, Yangyang; Luo, Haiyun; Zou, Xiaobing; Wang, Xinxin ^[1]

---

1. Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)

In order to investigate the influence of electrode radius on the characteristics of cathode fall thickness, experiments of low-pressure (20 Pa ≤ p ≤ 30 Pa) abnormal glow discharge were carried out between parallel-plane electrodes in different radii keeping gap distance unchanged. Axial distributions of light intensity were obtained from the discharge images captured using a Charge Coupled Device camera. The assumption that the position of the negative glow peak coincides with the edge of cathode fall layer was verified based on a two-dimensional model, and the cathode fall thicknesses, d{sub c}, were calculated from the axial distributions of light intensity. It was observed that the position of peak emission shifts closer to the cathode as current or pressure grows. The dependence of cathode fall thickness on the gas pressure and normalized current J/p{sup 2} was presented, and it was found that for discharges between electrodes in large radius the curves of pd{sub c} against J/p{sup 2} were superimposed on each other, however, this phenomenon will not hold for discharges between the smaller electrodes. The reason for this phenomenon is that the transverse diffusions of charged particles are not the same in two gaps between electrodes with different radii.

• OSTI ID: 22408142
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 2 Vol. 22; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM CURRENTS
CAMERAS
CATHODES
CHARGE-COUPLED DEVICES
CHARGED PARTICLES
DIFFUSION
EMISSION
GLOW DISCHARGES
IMAGES
PRESSURE RANGE PA
THICKNESS
TWO-DIMENSIONAL CALCULATIONS
VISIBLE RADIATION