Ion Cluster Formation by Nonthermal Plasma Induced by Pulse Corona Discharge Toward Indoor Air Cleaning

During pulsed corona discharges, both negative and positive ions react with moisture to generate ion clusters. These ion clusters are useful for cleaning environmentally hazardous materials such as hazardous chemicals, pollutants, and allergens. In this study, numerical simulations are carried out on the ion cluster formation of such ion-generation devices. The behavior of streamer evolution and cluster formations is simulated, and we show that the clustering progresses toward H
₃
O
⁺
(H
₂
O)
₄
and O
₂
^-
(H
₂
O)
₄
when the chemical species of H
₃
O
⁺
(H
₂
O)n and O
₂
^-
(H
₂
O)n (n = 0-5) are considered. Ion number densities measured in the study are smaller than those calculated because of known differences between the numerical model and the experimental apparatus (in particular, the difference due to the loss of ions in the path of the chamber). The evaluation of the lifetime and diffusion coefficients of the ion clusters could be important.