Ruhr-Universität Bochum
Uni von A-ZA-Z


SFB 591


SFB 591
Universelles Verhalten gleichgewichtsferner Plasmen
I - Die Uni entdecken II - Die Uni entdecken III - Die Uni entdecken IV - Die Uni entdecken V - Die Uni entdecken
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SFB 591 » Projekte » A8


Non-equilibrium phenomena in and induced by plasma boundary sheaths: Resonances, heating, and transport

Project manager

Prof. Dr. Ralf Peter Brinkmann
Institut für Theoretische Elektrotechnik
Ruhr-Universität Bochum

Prof. Dr. Uwe Czarnetzki
Institut für Experimentalphysik V
Ruhr-Universität Bochum

Dr. Karl-Ulrich Riemann
Institut für Theoretische Physik I
Ruhr-Universität Bochum

Mitarbeiter »


If a plasma comes into contact with a material surface, it reacts in building up of a thin, non-neutral zone, the plasma boundry zone. Here prevail strong electrical fields and spatial gradients, which shift the plasma into a pronounced nonequilibrium state and induce appropriate transportation phenomena. With the technically particularly important high frequency plasmas in addition the effect of the external modulation is taken into account. This has special influence in the boundry zone and prevents, as source of free energy, the relaxation into the equilibrium.

The subject of subproject A8 is the experimental and theoretisshe investigation of non-equilibrium phenomena in the boundry zone, whereby special attention is given to the case of the high frequency-modulated low pressure plasmas. The goal consists of the development of a detailed physical understanding of the observed processes. From the beginning, kinetic conceptions are to be worked out, the observable phenomena of the (spatial) transport and the heating are therefore seen as a special case of a more comprehensive phenomenon namely "Transport in phase space". Due to their different mass and charge of the different species of plasma, they each require their own models, these are however closely bound together by the strong reciprocal effect over the field as well as by the impacts with one another. In case of the the ions there is to be examined, how the particles separate in wall proximity from the ambipolar transportation regime of the bulk and get inserted into the pronounced kinetic regime of the layer, and which influence this process has on the details of the energy- and angle-distribution. On the other hand, in case of the electrons the conception is, that especially transient fields force the deviation from the impulse equilibrium and thus create a transport. Special attention rests therefore on the phenomenon of the smooth and stochastic heating. Finally also the dynamics of the neutral particles in the boundry zone is to be examined. These are not directly affected by the electrical field, but are for themselves far from the state of equilibrium: Sources of energetic neutrals are e.g. flexible and charge exchange impacts in the layer, or the neutralization and following reflection of fast ions from the wall.

The project work is split up into experimental investigations, theoretical analysis coupled with application- and experiment-near modelling and simulation. Due to the experiments a clear and complete insight into the dynamics of material plasmas is to be established on the basis of a parameter range as broad as possible.Particularly selected mechanisms and/or regimes are to be understood in detail and so conceptual clarification of the procedures is to be reached by the theoretical analysis.

The long-term goal of the project mainly consits of the development of a complete understanding of the procedures found in boundry layers of low pressure plasmas, especially the clarification of transport processes and heating mechanisms in self-consistent fields. An experimentally and theoretically secured picture of the phenomena is to be sketched and the connection between external parameters and decharging behavior to be understood. This is not only of fundamental physical interest, but also of outstanding technological importance.

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