| AVS 54th International Symposium | |
| Plasma Science and Technology | Tuesday Sessions |
| Session PS2-TuA |
| Session: | Plasma Sources |
| Presenter: | S.G. Belostotskiy, University of Houston |
| Authors: | S.G. Belostotskiy, University of Houston V.M. Donnelly, University of Houston D.J. Economou, University of Houston |
| Correspondent: | Click to Email |
Experimental I-V characteristics of DC microdischarges in helium were obtained at different operating pressures (P = 300 - 800 Torr). Since the interelectrode gap was relatively small (L = 300 µm), the voltage drop across the discharge was approximately equal to that across the cathode sheath. It was found that the scaling laws obtained by the classical theory of the cathode layer developed by von Engel and Steenbeck (i.e., the cathode voltage is a function of current density divided by the square of the pressure - Vc = f(j/p2)) are not applicable to microdisharges due to the influence of gas heating. For example, the voltage drop at p = 700 Torr was 40 Volts higher than that at p = 300 Torr for the same reduced current density J = 3 µA/(cm2*Torr2). A new semi-analytical model of the cathode layer that accounts for neutral gas heating was developed. Model predictions were in agreement with the experimental I-V characteristics. The model can be used to quantify the influence of neutral gas heating on microdischarge performance.