BIPOLAR CHARGING OF AEROSOL-PARTICLES IN ELECTROPOSITIVE GAS OF HIGH-PURITY

Electrification of fine particles in high-purity electropositve carrie r gas, passing through a radioactive charger, was studied theoreticall y. Particle charging occurs due to attachment of ions of both polariti es and free electrons. Because the electron mobility is huge in compar ison with typical ion mobilities, their presence in the gas manifests itself in a significant asymmetry in charging and in appearance of the maximum of the negatively charged particle concentration as a functio n of the ionization rate. A mathematical model of the charger, based o n the balance laws for ions, electrons, and particles of various fract ions is proposed. It is shown to explain the complicated behavior of t he concentrations of the charged particle fractions, observed earlier in experiments.