The origin and evolution of water aerosol inside a laboratory ball lightning
A.A. Cheremisin1, E.A. Shishkin1, A.M. Baklanov1, M.A. Soloviev1, V.V. Karasev1, A.A. Onishchuk1, V.N. Parmon2
1V.V. Voevodsky Institute of Chemical Kinetics and Combustion of the Siberian Branch of the RAS, Novosibirsk, Russia
2Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia
Keywords: water aerosol, plasmoid, ball lightning
Abstract
The work studies the origin and evolution of water aerosol in the so-called plasmoid, which is generated by a high-voltage discharge above a water surface in the form of a luminous spherical object and considered a laboratory analogue of natural ball lightning. The laboratory ball lightning was investigated not only in situ using non-contact probing techniques, but also by sampling with the use of specially designed devices. Water vapor condensation occurs during the glowing stage of the plasmoid, implying that the internal temperature drops to at least 100 °C. The experimental data indicate that the water droplets inside the plasmoid are not luminous. After the glow ceases, a phantom resembling the spherical structure of the plasmoid persists for about 1 s; inside this phantom, water aerosol can still be observed. The existence of a “shell” confining the spherical object is plausible not only during the glow, but also for a certain time thereafter. The aerosol particles produced by erosion of the central electrode during the discharge were measured with a diffusion spectrometer. Their sizes lie in the submicron range and are substantially smaller than those of the water droplets inside the plasmoid. The principal conclusion is that the long-lasting glow results from chemical processes occurring in the gas phase of the plasmoid rather than from high-temperature heating of the gas or from emission by aerosol particles.
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