In a DBD it is not possible to measure the electrical values of the plasma directly. To determine them it is necessary to separate the capacitive from the real current component within the gap. To overcome this problem Liu and Neiger have published an analytical method to determining the plasma values from the lamp voltage and current1.
This method is very complex and needs some simplification to differentiate and integrate the voltage and current values over time so that a real time analysis is not possible. Based on this model, Roth and Schwarz developed an electrical setup to measure the inner values directly2. We have developed this method further and have now the possibility to determine the plasma voltage, current for pulsed operation. Based on this measurement method we have developed an electrical model to describe the role of space charges inside the gap. With the model it is possible to amount the electrical field of space charges integrated as voltage ucharge. The difference between the determined voltage ucharge and the measured gap voltage describes the effective exciting voltage uexcite.
Examples of sinusoidal and pulsed excitation show that this model could describe the development of space charges
correctly. The new defined ignition voltage uexcite,max shows, despite the old definition of ugap,max, no dependence on the voltage waveform and describes the behavior of preionization correctly.
1. Shuhai, L. and M. Neiger, J. Phys D: Appl. Phys., 2003, 36(24): p. 3144-50
2. Roth, M., Neiger, M., Measurement of Internal Electrical Properties in AC PDP-Like Configurations Using a Novel Measuring Method, 21st International Display Research Conference, 2001, Nagoya