Dust Acoustic Waves Triggered by Cloud to Ground Lightning

Summary form only given. Powerful electric currents and transient luminous events (sprites, blue jets and gigantic jets) have been detected in discharges between thunderclouds and the lower ionosphere. The occurrence of such phenomena is strongly related to the occurrence of ultra low frequency (ULF~3-50 Hz) waves and to the occurrence of positive polarity cloud-to-ground flashes. We present a novel mechanism that shed light on the origin and propagation of the observed ULF waves. Ionospheric clouds are composed of charged ice/smoke particulates, protons, electrons and neutrals. Our objective here is to show that such partially ionized dusty plasmas with streaming electrons in ionospheric clouds may support unstable dust acoustic waves (DAWs~3-12 Hz). For our purposes, we employ a multifluid dusty plasma model and derive the dispersion relation for modified DAWs in a magnetized, collisional plasma. The dispersion relation is analyzed numerically to obtain the growth rate and threshold