Preface

We are pleased to present the Proceedings of 20th International Workshop on Magneto-Plasma Aerodynamics (WSMPA 2021) which was held in Moscow on May 25 – 27, 2021 at Joint Institute for High Temperatures of the Russian Academy of Sciences (JIHT RAS). Every year this Workshop is organized by JIHT RAS under Scientific Council for Direct Energy Conversion, Scientific Council for Fluid Mechanics and Scientific Council for Low Temperature Plasma Physics of the Russian Academy of Sciences. The second year the Workshop took place as online conference (using Zoom) due to covid-19 and therefore quarantine and travel restrictions. The objective of the Workshop is to provide forum for presentation and discussion of recent progress in science and technology on magneto-plasma aerodynamics. Analytical and experimental studies and their results of gas discharge, physics of shock waves, plasma assisted ignition and combustion, MHD energy conversion, physical gas dynamics of high-speed airflows and their applications were presented and discussed the meeting. At the 20th Workshop there were presented 57 works in profiled sections: shock waves, electrical discharges, plasma assisted ignition and combustion, plasma aerodynamics and gasdynamics, and related problems. Oral resentation time including questions was 20 minutes. 33 selected articles are published in this collection of papers and we are grateful to IOP Publishing for cooperation. Valentin Bityurin, Chairman of WSMPA 2021, Tatiana Kuznetsova, Scientific Secretary of WSMPA 2021 List of Program Committee and Local Committee are available in this pdf.

Natural and artificial Ball Lightning in the Earth’s atmosphere

Issues related to ball lightning of natural origin and its laboratory modeling in air are presented. The data on the main known researchers of these issues are given. Experiments on modeling long-lived luminous formations and artificial ball lightning are discussed. Observational data on ball lightning are presented. Methods of statistical analysis of observational data on ball lightning are considered. The theoretical models of natural ball lightning are briefly discussed. The book is aimed for senior students of physics and physics and technology departments of universities, as well as for scientists and engineers who deal with complex systems containing low-temperature plasma, plasma aerodynamics, geography and geophysics.

Gasdynamic Flow Control by Ultrafast Local Heating in a Strongly Nonequilibrium Pulsed Plasma

Abstract— The paper presents a review of modern works on gasdynamic flow control using a highly nonequilibrium pulsed plasma. The main attention is paid to the effects based on ultrafast (on the nanosecond time scale for atmospheric pressure) local gas heating, since, at present, the main successes in controlling high-speed flows by means of gas discharges are associated with this thermal mechanism. Attention is paid to the physical mechanisms responsible for the interaction of the discharge with gas flows. The first part of the review outlines the most popular approaches for pulsed energy deposition in plasma aerodynamics: nanosecond surface barrier discharges, pulsed spark discharges, and femto- and nanosecond optical discharges. The mechanisms of ultrafast heating of air at high electric fields realized in these discharges, as well as during the decay of the discharge plasma, are analyzed separately. The second part of the review gives numerous examples of plasma-assisted control of gasdynamic flows. It considers control of the configuration of shock waves in front of a supersonic object, control of its trajectory, control of quasi-stationary separated flows and layers, control of a laminar–turbulent transition, and control of static and dynamic separation of the boundary layer at high angles of attack, as well as issues of the operation of plasma actuators in different weather conditions and the use of plasma for the de-icing of a flying object.