Observation of Long-Lived Plasma Formations in a Toroidal air Vortex under Normal Conditions

Abstract

Purpose. Experimentally investigate the difference between the characteristic lifetime of plasma formations in a stationary and rotating toroidal air volume under normal ambient conditions.Methods. Experimental study of plasmoids was carried out by videotaping with a high-speed camera with subsequent frame-by-frame processing of the recording. Generation of plasmoids was performed by mechanical rupture of the plasma cord of the welding arc in the field of permanent magnets. The creation of toroidal rotation of the plasma formation in air occurs when it passes through a hole in a solid screen. Numerical estimation of mechanical forces acting on ions in the air vortex is performed by order of magnitude using experimental data.Results. Two different in design laboratory installations for observation of plasma formations in air under normal external conditions have been created. The lifetime of such "long-lived" plasmoids in air is equal to about two milliseconds, which significantly exceeds the lifetime of a plasma-forming welding arc in the free state under the same conditions. The increase in plasmoid lifetime is considered and explained within the framework of mechanical ideas about spatial separation of heavy and light ions inside the plasma under the action of inertia forces as a result of rotational motion of air. The proposed mechanical model of the phenomenon is obviously simplified and does not take into account diffusion, recombination and other related phenomena, since the main and only difference between the observed "longlived" and "ordinary" plasmoids lies in the nature of the mechanical motion of the medium.Conclusion: Two experimental setups allowing to generate and observe the behavior of plasma formations with a characteristic lifetime of the order of two milliseconds are created and described. The results of observations indirectly confirm a simple mechanical hypothesis about the connection between the lifetime of a free plasma formation and the rotational motion of the gas inside it.