Date: March 13
Hour: 4 p.m.
Venue: PA1 auditorium, Alameda Campus
«Uwe Czarnetzki will deliver an IST Distinguished Lecture / IPFN and DF Colloquium titled “Kinetic effects in low-temperature plasmas”, on March 13th, 2024. The event is co-organised by the N-PRiME group of the Institute for Plasmas and Nuclear Fusion, and the scientific area of Plasmas, Lasers and Nuclear Fusion of the Department of Physics at Instituto Superior Técnico.
Abstract
Some of the most important and fascinating phenomena in plasmas are related to kinetic effects, e.g. collisionless heating or transport phenomena. Naturally, the distribution functions of the charged particles are at the heart of the problem. The distribution function is a result of the complex interaction of the particles with the gas atoms/molecules and the electric field structure.
On the other hand, the electric field structure itself is usually resulting from the coupling to the electrons. Further, in low-temperature plasmas, the non-equilibrium conditions in these systems lead in general to distribution functions that deviate significantly from the standard Maxwellian distribution.
While the common way of addressing kinetic effects is based on the use of the Boltzmann equation, an alternative approach for describing local Ohmic and non-local (stochastic) heating is provided by the Fokker-Planck equation supplemented by the Langevin equation. One advantage of this approach, as compared to the Boltzmann equation, is probably a more natural insight into physics.
Local and non-local interactions of electrons with fields are illustrated by selected examples. This includes the problem of self-consistent field structures, global distribution functions as well as tailored periodic field structures. Last but not least, it will be shown that non-local effects can be important even under conditions of high collisionality. Finally, an outlook for further work on kinetic effects will be provided.
Speaker bio
Professor Czarnetzki studied physics at the University of Essen in the 1980s and concluded his PhD (1991) and Habilitation (1999) in experimental physics at the same University. He is a full professor of physics at the Ruhr University Bochum (RUB) since 2001, and was dean/deputy dean of the Faculty for Physics and Astronomy of the (RUB) in 2008-2012 and 2014-2015.
He has been a fellow of the Institute of Physics IOP since 2009, a member of the External Advisory Board of the DOE Plasma Science Center since 2010, and appointed professor at Osaka University, Japan, since 2017. His research interests are well-balanced between experiments and theory. This requires well-designed plasma sources (some proposed by Czarnetzki, like INCA), advanced diagnostics (e.g. using and developing advanced laser diagnostic techniques, with lasers ranging from fs to CW operation and wavelengths from the UV to the IR), and the development of analytical models often combined with simulations (focusing on the kinetic description of plasmas).
He received several prestigious awards, such as the Plasma Physics Innovation Prize of the European Physical Society (2010), the Jade-Award from the Japan-Deutschland Foundation for outstanding merits on German-Japanese scientific and cultural Exchange (2015), the von Engel & Franklin Prize of the International Conference on Phenomena in Ionized Gases (administered by the Board of Physical Sciences, University of Oxford) (2017), the ISPlasma Prize for outstanding achievements in the field of Plasma Science and its Applications (2018), and the Plasma Materials Science Hall of Fame Prize (2024) ‘for the excellent achievements in many years of outstanding research on physical analysis of phenomena related to low-temperature plasma materials processing, and proposals for original plasma processing equipment’.»
