Development of a method for the measurement of electric charges of aeolian sands

Abstract

Laboratory experiments were carried out using an apparatus specially designed for measuring the electric charge of aeolian sand particles. The dependence of the electric charges on wind speed, particle size and mineralogical composition is investigated using three kinds of sand samples, namely, the desert sand, quartz sand and olivine sand. It is suggested that the charged characteristics of each mineral is one of the important factors which affect on the movements of sand in the desert area. The electric charge of sand particles increases with increasing wind speed and reaches a maximum, then decreases when the sand transportation process changes from saltation to suspension.

アイオリス砂粒の電荷を測定するために特に設計した装置を用いて実験を行った。砂漠の砂、石英砂およびかんらん石砂の3種類の砂試料を用いて、電荷の風速、粒径および鉱物学的組成依存性を調べた。その結果、各鉱物の荷電特性は砂漠地帯の砂の移動に影響を及ぼす重要なファクタの1つであることが示唆された。砂粒の荷電は風速と共に増加し、やがて最大値に達するが、砂の輸送プロセスが移動から静止へと変化すると減少に向かう。