Microdischarges between ice particles

Abstract

A laboratory experiment is performed in a cold chamber to produce microdischarges between frozen hydrometeors. A charged icicle is placed close to an uncharged one connected to a transient analyser. The electric current signature obtained during each event is then studied and characterized in function of both temperature and net charge. The existence of a transition temperature of about −15°C is detected, whereas net charge clearly governs the microdischarge characteristics. Furthermore, the radiated electric field is calculated and the spectral analysis, by means of fast Fourier transform, shows that this elementary phenomenon radiates within the VHF range. Comparisons are made with previous similar work by Chauzy and Kably (1989) on microdischarges between water drops.

Electrical discharges and broadband radio emission by Martian dust devils and dust storms

“…Farrell et al [2002] measured radio emission by terrestrial dust devils in the ULF/ELF range, Farrell et al [1999] predicted higher frequency radio emission by glow discharges from single dust grains, and our calculations indicate microwave emissions. This phenomenon can be compared with well‐established theory, laboratory experiments, and observations of microdischarges between hydrometeors, and aerosol particles [ Atkinson and Paluch , 1966; Barreto , 1969; Keeney , 1970; Keith and Saunders , 1988; Chauzy and Kably , 1989; Coquillat et al , 1995], which show that microdischarges between colliding particles produce microwave emission.…”

Total lightning activity in thunderstorms over Paris

“…On the other hand, hailstones are large particles that can enhance the local electric field, which is better for corona emission. If they undergo wet growth leading to the presence of a quasi-liquid layer at their surface, their electric conductivity is close to that of water, which allows comparable electric currents during microdischarges (Coquillat et al, 1995). But they remain non-deformable particles and are consequently less efficient in the first step of the initiation of a microdischarge.…”

Lightning characterization through acoustic measurements

“…Cette séparation des charges provoque une activité électrique dans le nuage et la production de micro-décharges entre les particules chargées. Coquillat et al [1995] étudient l'initiation de micro-décharges électriques entre des particules de glaces à l'aide d'une expérience de laboratoire. Ils montrent que le champ électrique rayonné par ces décharges est à très haute fréquence.…”