Dusty Plasmas
- Dusty plasmas are complex systems where dust (particles in the size range of a micrometer) are immersed in a low pressure gas discharge (consisting of atoms, ions, and electrons). It happens, that these dust particles become highly charged due to the constant influx of electrons and ions, and as a result of this electric charge, they strongly repel each other. This inter-particle interaction can be so strong, that the dust cloud forms a regular crystal. The big advantage of these systems is, that the dust particles are big and slow enough to be easily detected by video microscopy, but they are small and a typical cloud consists of many thousand of them, making the way free for collective effects to be dominant.
- Under laboratory conditions two-dimensional and layered systems are easy to form, small 3D clusters are also possible. To study large 3D configurations microgravity conditions are necessary, therefore experiments on the International Space Station and parabolic flights are performed routinely.
- In my view, these systems serve as a model systems for the atomic world. One can study classical phenomena (not requiring quantum mechanical description), like solid-liquid phase transition, laminal and turbulent flow, diffusion, heat conductivity, wave propagation, crystal formation, etc. on the most fundamental (kinetic) level, because the experiments provide the trajectories of every particles in the system.
- We have designed and built our experimental setup by 2009, which already provided useful insight into the wave dispersion properties of bilayer systems.
Strongly Coupled Plasmas
- Strongly coupled plasmas are many-particle systems consisting of electrically charged particles where the electrostatic interaction energy dominates over the thermal kinetic energy. Dusty plasmas are such systems, but there is a lot more: dense hydrogen in stellar interior, H-He mixture in the core of Jovian planets, the crust of neutron stars, etc. Exotic examples are: electrons in graphene, quark-qluon plasma near the hadronization transition, etc.
- Our contributions to this wide field are mostly numerical simulations of classical many-particle systems. We usually study structure, wave dispersion properties and transport phenomena in 2D, 3D and layered systems.
Low-pressure Gas Discharges
- A low pressure gas discharge forms when current is driven through a (usually insulating) gas. In this case the electrons collide with the gas atoms, which may result in excitation or ionization of the atom. Stationary state is reached when the gas-phase ionization + surface electron emission compensates the losses on the surfaces.
- Some of the prominent examples for devised based on gas discharges are: modern light sources, plasma display panels, gas lasers, industrial plasma reactors (for micro-electronic fabrication, surface treatment of all kinds, etc.).
- In our laboratory we have the chance to investigate principle properties (electric characteristics, emission spectra, light distribution, etc.) of noble gas discharges with direct current or radio frequency drive.
- With sophisticated numerical models (simulations combining particle and fluid mechanical description) we are able to study the formation and operation of low-pressure gas discharges in great detail.