Optical and Electrical Diagnostics of a High-Frequency Glow–Arc Discharge and Its Application to the Synthesis of Carbon Nanofibers

In this paper, a detailed diagnostic of an AC glow-to-arc discharge transition is presented. The behavior of the temporal evolution of voltage and current discharges is studied under an atmosphere of helium-methane. In order to determine the rotational temperature, an optical emission-spectroscopy analysis from glow-to-arc regime discharge is carried out, where the OH and bands, respectively, which are situated at 306.357 nm (A²Σ⁺, ν=0→X²Π, ν\´=0) and 516.52 nm (d³Π_g, ν\´=0→a³Π_u, ν"=0), are used. Several metallic atomic lines were used to calculate the electron temperature. The principal discharge parameters, such as temperature and electron density in the arc regime, are determined. As an application of this glow-arc discharge, the synthesis of carbon nanofibers is reported.