THEORETICAL AND EXPERIMENTAL-STUDY OF LOW-TEMPERATURE, CAPACITIVELY COUPLED, RADIOFREQUENCY HELIUM PLASMAS

A comparison is made of one-dimensional theoretical simulations with m easured densities of electrons and He metastables in a Gaseous Electro nics Conference Reference Cell. The theory attempts to be as ab initio and complete as necessary for describing a He plasma. The basic theor etical description incudes the time-dependent, electric-field-consiste nt Boltzmann equation for the electrons, inertial fluid equations for the heavy particles, and a multilevel model of the He excitations. The novel numerical algorithms are rapidly convergent. The experimental a nd theoretical absolute number densities are generally within a factor of 2 for both the electron plasma density and the metastable densitie s. In addition the spatial variation of the metastable populations (si nglet and triplet) between the electrodes is well reproduced.