Dusty Plasmoids Ejected from Silicon by Localized Microwaves - Reflection Analysis

This paper presents an experimental and theoretical investigation of plasmoids, in forms of fireballs and fire-columns, obtained by directing localized microwaves (~0.8 kW at 2.45 GHz) into a solid substrate (e.g. silicon) in a microwave cavity. The plasmoid is blown up from the hotspot created in the silicon substrate to the air atmosphere within the microwave cavity. The experimental diagnostics utilize the microwave reflections from the dusty plasmoid in order to estimate its effective permittivity. Taking into account also prior measurements by optical spectroscopy and small-angle X-ray scattering, the electron density is estimated as 18 -3 3 10 m e n   within the fireball.