(2021) Cejas, Ezequiel; Prevosto, Leandro; Minotti, Fernando; Ferreyra, Matías; Chamorro, Juan Camilo; Fina, Brenda
The cathode-sheath region of a discharge in atmospheric pressure air with a flat copper cathode is numerically investigated by using a simple
fluid model that takes into account non-local ionization. The effects of the cathode temperature are considered. Results are obtained in a
wide current density range of 1–102 A/cm2
, which spans from normal glow discharge, through abnormal glow discharge, up to the early
stages of the arcing transition. It is shown that the glow-to-arc transition arises from a field-emission instability at the cathode when the cur rent density is larger than 10 A/cm2
, i.e., when the cathode field exceeds a critical value of about 45 V/lm for the conditions considered. It
is also shown that the cathode temperature significantly influences the cathode-sheath region. The proposed model is validated by comparing
the numerical results with available experimental data.
