Topic：Electric breakdown in thunderstorms and plasma technology – chances and puzzles

Speaker: Prof. Ute Ebert Centre for Mathematics and Computer Science (CWI, Amsterdam), and Eindhoven University of Technology, The Netherlands

时 间：12月3日（周一）早上9：00

地 点：清华大学西主楼（电机系）3区102

邀请人： 曾 嵘 教授、蒲以康教授

Abstract:

Electric breakdown of gases occurs in thunderstorms and in a wide range of applications in plasma and high voltage technology. While application fields such as plasma processing, plasma medicine and plasma assisted combustion are progressing due to new means of generation, diagnostics and modeling of pulsed plasma discharges, our understanding of lightning physics is challenged by transient luminous events (elves, halos, sprites, jets and gigantic jets) above thunderstorms, and by high energy processes related to active thunderstorms like terrestrial gamma-ray flashes and clear signatures of nuclear reactions in our atmosphere. I will explain the common grounds of these natural and technical phenomena, and I will discuss the sequence of early discharge stages, from discharge inception through the streamer discharge evolution to leaders and sparks. A key feature are the extremes of the electron energy distribution in certain discharge stages up to electron runaway and to the high energy atmospheric processes in thunderstorms.

About the speaker:

Ute Ebert studied physics at the University of Heidelberg, Germany, and at the Hebrew University in Jerusalem, Israel, and she defended her PhD on the renormalization group analysis of long polymer chains at the University of Essen, Germany, in 1994. As a postdoc at the University of Leiden, The Netherlands, she switched to nonlinear dynamics and pattern formation, in particular, in application to streamer ionization fronts. In 1998 she gained a staff position at the Netherlands’ national research Centre for Mathematics and Computer Science (CWI) in Amsterdam. Since 2002, she leads the research group “Multiscale Dynamics” at CWI, and she is a full professor of physics in part-time at Eindhoven University of Technology (TU/e). In this double role, she has built up a wide collaboration network with numerous projects together with plasma physics, high voltage engineering and mechanical engineering at TU/e, with physicists at the Dutch radio telescope LOFAR (http://www.lofar.org) and with a European and international network for thunderstorm observations from space (in particular, through the ASIM mission (https://www.asim.dk)) and from ground.