Microwave-ignited DC-plasma ejection from basalt: Powder-generation and lightning-like effects

A phenomenon of dusty plasma ejected from basalt is presented, in the form of a stable, long-lived fire-pillar, solely sustained by a direct-current (DC) supply. The plasma is emitted to the air atmosphere from a molten hotspot, initially created in the basalt rock by localized microwave-heating (LMH). After an LMH-to-DC transition, the plasma column is solely sustained as a fire-pillar of ∼2 cm diameter, ∼4-cm height using a DC supply of ∼0.2 kV, ∼5 A, steadily lasting for periods longer than 3 min. The dusty-plasma products, accumulated in a powder form, consist of micro- and nanoparticles of basalt's components, including oxides of Si, Na, Fe, P, K, Mg, and Ti. The experimental conditions for the DC sustainability of basalt's dusty-plasma column are analyzed by various theoretical estimates. A possible relevance of these laboratory observations is attributed to atmospheric fire-pillar-like effects, associated, for instance, with volcanic-, ball-lighting, and lunar dusty-plasma phenomena. A potential application, utilizing this effect of DC-sustained dusty-plasma columns, is proposed for the direct extraction of mineral powders from rocks.