A laboratory test of the electrification phenomenon in wind-blown sand flux

The measured data in the wind-tunnel tests show that the wind-blown sand pa rticles acquired a negative charge when their diameters are smaller than 25 0 mum and positive charge when their diameters are larger than 500 mum, whi ch confirms Latham's assumption that the large particles in wind-blown sand flux acquired positive charge while negative charge developed on small one s. In the meanwhile, the measured data also show that the average charge-to -mass ratio for wind-blown sand particles decreases with the increase of th e particle diameter and the wind velocity, and increases with the rise of h eight. The electric field in wind-blown sand flux is mainly formed by the m oving charged sand particles. Its direction is vertical to the Earth's surf ace and upward, which is opposite to that of the fair-weather field. The el ectric field increases with wind velocity and height increasing. These expe rimental results will lay the foundation for developing the theoretical ana lysis of the electrification phenomenon in wind-blown sand flux.