Measurements of Cylindrical Ice Crystal Growth Limited by Combined Particle and Heat Diffusion

We present measurements of the growth of long columnar ice crystals from water vapor over a broad range of temperatures and supersaturation levels in air. Starting with thin, c-axis ice needle crystals, we observed their subsequent growth behavior in a vapor diffusion chamber, extracting the initial radial growth velocities of the needles under controlled conditions. Approximating the hexagonal needle crystals as infinitely long cylinders, we created an analytical growth model that includes effects from particle diffusion of water molecules through the surrounding air along with the diffusion of heat generated by solidification. With only minimal adjustment of model parameters, we obtained excellent agreement with our experimental data. To our knowledge, this is the first time that the combined effects from particle and heat diffusion have been measured in ice growth from water vapor. This analysis further provides an accurate method for calibration of the water-vapor supersaturation levels in experimental growth chambers.