2010/07/16 by Alexander Heifetz, Hual-Te Chien, H.-T. Chien +5
Engineering · Physics and Astronomy · #Aerosol Filtration and Electrostatic Precipitation #Atomic physics #Environmental science #Extremely high frequency #Materials science #Millimeter #Optics #Orbital Angular Momentum in Optics #Particle Dynamics in Fluid Flows #Physics #Scattering #physics.ao-ph
paper · pdf · doi:10.1016/j.jqsrt.2010.08.001
published as Journal of Quantitative Spectroscopy and Radiative Transfer 111, 2550-2557 (2010) · 18 pages, 8 figures
arxiv created 2010/07/16 · openalex publication_date 2010/08/05 · arxiv updated 2014/06/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigated 94GHz millimeter wave (MMW) scattering from neutral and charged water mist produced in the laboratory with an ultrasonic atomizer. Diffusion charging of the mist was accomplished with a negative ion generator (NIG). We observed increased forward and backscattering of MMW from charged mist, as compared to MMW scattering from an uncharged mist. In order to interpret the experimental results, we developed a model based on classical electrodynamics theory of scattering from a dielectric sphere with diffusion-deposited mobile surface charge. In this approach, scattering and extinction cross-sections are calculated for a charged Rayleigh particle with effective dielectric constant consisting of the volume dielectric function of the neutral sphere and surface dielectric function due to the oscillation of the surface charge in the presence of applied electric field. For small droplets with (radius smaller than 100nm), this model predicts increased MMW scattering from charged mist, which is qualitatively consistent with the experimental observations. The objective of this work is to develop indirect remote sensing of radioactive gases via their charging action on atmospheric humid air.