Electrodynamic trapping and manipulation of ice crystals

Abstract

Abstract We have developed a double‐ring double‐disk electrodynamic balance with humidity control provided by an internal thermal diffusion chamber to study several atmospherically important processes involving 10‐200 μm ice particles. the balance constants needed to quantify the particle size and mass were determined by a three‐dimensional relaxation‐method calculation of the non‐axisymmetric electric fields, and by experimental measurement of the onset of particle stability using polystyrene latex microspheres of known size and mass. We have levitated frost particles of various shapes and sizes under a range of atmospherically relevant temperature and humidity conditions. the measured mass changes during growth and sublimation are consistent with predictions based on vapour and thermal diffusion to equivalent spheres. the electrodynamic balance is shown to be a useful tool for exploring single particle growth and sublimation rates, and for measuring their light‐scattering characteristics.