Tailoring of electron energy distributions in low temperature plasmas

Assuming a background Maxwellian electron distribution we investigate the effects of tailoring the tail of the distribution upon the plasma density and electron temperature in a capacitive discharge. Taking the latter to be in the intermediate pressure regime the main effect of the tail is to modify the rate coefficients for ionization and excitation, and hence to alter the collisional energy loss per electron-ion pair created. We demonstrate that the background temperature can be suppressed and the electron density increased by enhancing the tail population. The model is applied to a typical set of low temperature conditions in argon and the changes in temperature and density calculated. Injecting 100 eV electrons into an argon plasma under very similar conditions to those of the application of our model, the corresponding densities and temperatures are measured. Good qualitative agreement is found.