It is shown that particle diffusion in the afterglow of a dusty plasma can be used to establish several properties of the active plasma. Specifically, the ratio of the average mass of light negative and positive ions, and a limit for the ratio of electron to iron charge densities can be determined. From the afterglow decay of visible particles, with and without electrode bias, the charged fraction of particles can be measured. An afterglow ambipolar-diffusion model is developed to relate this Neutral fraction to the densities and masses of electrons and light ions in the active plasma. We then use this technique to analyze a silane radio-frequency plasma. In the active plasma positive charge is dominated by small SiyHn+ cations, and the negative charge by small SixH-m anions, with x and y
Journal of Applied Physics
afterglow, dusty plasma, particle diffusion
and Gallagher, A.
Plasma Charge-Density Ratios in a Dusty Plasma, Journal of Applied Physics
(Accessed February 27, 2024)