MICRODISCHARGES BETWEEN ICE PARTICLES

A laboratory experiment is performed in a cold chamber to produce micr odischarges between frozen hydrometeors. A charged icicle is placed cl ose to an uncharged one connected to a transient analyser. The electri c current signature obtained during each event is then studied and cha racterized in function of both temperature and net charge. The existen ce of a transition temperature of about -15 degrees C is detected, whe reas net charge clearly governs the microdischarge characteristics. Fu rthermore, the radiated electric field is calculated and the spectral analysis, by means of fast Fourier transform, shows that this elementa ry phenomenon radiates within the VHF range. Comparisons are made with previous similar work by Chauzy and Kably (1989) on microdischarges b etween water drops.