A simple model for cathodic electronic emission enhanced by low-energy ions in high-pressure arcs

The influence of slow ions on the electronic emission of a cathode in a high-pressure electric arc is investigated. As a first approach, a simple model is introduced, where solving the stationary Schrödinger equation is reduced to integrating a one-dimensional second-order differential equation. We have found that the electronic current may be enhanced through two mechanisms: a non-resonant process related to the lowering of the potential barrier and a resonant mechanism involving bound states of the ions. The non-resonant process is found to be dominant. The influence of various parameters such as ionic density, cathode temperature and charge states of the ions on amplification coefficients is analysed.