Figure 5. The numerically simulated electric field strength, in comparison with the experimental measurements at different heights²⁸.

(a) uniform sands; (b) mixture sands. In wind-blown sand, the electric field at a given point P(x, y, z) due to a sand with charge q_i is given by , according to Coulomb's law, where ε₀ is dielectric constant and r is vector distance between the charged sand and the point P(x, y, z). Then the total electric field at the point P(x, y, z) due to all charged sands can be calculated by .