Alignment of fee Crystals due to Transient Electric Fields

Abstract

The alignment of columnar ice crystals due to the electric field surrounding a moving charged object, such as an aircraft, is modeled. The model allows the conditions of charge, velocity, ambient electric field, and size and shape of crystal to be specified. The electrical charge required to produce significant alignment effects can realistically be expected to be acquired by an aircraft in snowfall, given the model results and previous studies of the electrical characteristics of aircraft. The model predicts the orientation of crystals as they approach a charged object. Airborne observations of crystals from a two-dimensional imaging probe reveal similar alignment characteristics to those predicted by the model.