Evidence for Nanoparticles in Microwave-Generated Fireballs by Synchrotron X-Ray Scattering

The small-angle X-ray scattering (SAXS) method has been applied to study fireballs ejected from molten hotspots in borosilicate glass by localized microwaves [Dikhtyar & Jerby, PRL 96 045002 (2006)]. The fireball's particle size distribution, density, and decay rate in atmospheric pressure were measured. The results show that the fireballs contain particles with diameters of ~10 nm in clusters of ~64 nm with particles' average densities of ~10 cm. Hence, fireballs can be considered as a dusty plasma which consists of an ensemble of charged nanoparticles in the plasma volume. This finding is likened to the ball-lightning phenomenon explained by the formation of an oxidising particles' networks liberated by lightning striking to the ground [Abrahamson and Dinniss, Nature 403, 519 (2000)]