2. Low pressure, low temperature discharge

2.1 Diode discharge

To create a discharge in a gas between two conductive plates, the electrical rigidity of the medium must be overcome by applying a strong electric field up to an ignition voltage V _b . This potential V _b depends on the gas and the product of pressure × distance between electrodes.

The function V _b = f (p × d) is represented by Paschen curves (Figure 1 ). These curves are unique for each gas since they depend on the ionization ease of the element, and...