Criterion of Sheath Formation in Negative-Ion Plasma with Non-Extensive Electron Distribution

Abstract The criterion of sheath formation has been investigated for negative hydrogen ion plasma with non-extensive electron distribution. Standard hydrodynamic equations of ions are used to develop a generalized criterion for sheath formation. A comparison between the Boltzmann distribution of electrons and the non-extensive distribution towards sheath formation has been established. A regime categorization in the parameter space of collision and electronegativity, as well as the non-extensive q-parameter, has been discussed. The figures demonstrate the parameter regimes in which the electric field and ion inertia, collision and ionization, or all of them together, play a crucial role in the sheath formation.