Probing ionization characteristics of under-water plasma arc discharge using simultaneous current and voltage versus time measurement in carbon nanoparticle synthesis

Abstract

Abstract This study investigated the characteristics of plasma ionization that occurs during plasma arc discharge in water using carbon electrodes. The characterization of plasma ionization begins by observing the arc shape using a digital camera associated with voltage oscillation using current and voltage vs. time (I-t and V-t) characteristics. Furthermore, the ionization energy calculation is performed using simultaneous I-t and V-t measurement data. These calculations are then compared to the photon energy from the optical emission spectroscopy (OES). The results from the digital camera indicate four types of arc discharge in terms of shape and intensity related to voltage oscillation. Moreover, the energy calculations show that by using the I-t and V-t methods is possible to measure the plasma ionization detected not only in the range 1–4 eV but also in the outside range, including smaller than 1 eV and greater than 4 eV. These ranges correspond to the emission lines in visible light, infrared, and ultraviolet, respectively. In addition, the I-t and V-t methods can also measure the excitation and recombination energy of the arc discharge plasma ionization. This study reveals the possibility of investigating the characteristics of plasma ionization using simultaneous I-t and V-t measurements, which comprise an easier and more practical method in the diagnostics of carbon nanoparticle synthesis • A novel plasma diagnostic using I-t and V-t measurement were demonstrated as a probing method for ionization of arc discharge. • I-t and V-t measurement measurement reveals voltage oscillation during arc discharge for different states. • The difference in arc intensity and shape is due to the difference in plasma ionization characteristics of arc discharge. • Numerical analysis of single discharge energy is calculated from I-t and V-t data to obtain plasma parameters.