SMuK 2023 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 11: Poster I
P 11.16: Poster
Mittwoch, 22. März 2023, 14:00–15:30, HSZ EG
What's the rheology of electro-rheological plasmas? — •Michael Kretschmer1,2, Markus Thoma1, Andreas Schmitz1, Lukas Wimmer1, Thomas Nimmerfroh1, and Christian Schinz1 — 1Justus Liebig University, 1st Institute for Physics, Giessen — 2Technische Hochschule Mittelhessen, Abt. EI, Giessen, Germany
Negatively charged micron-sized particles inside a low-temperature plasma interact with each other and form strongly coupled Coulomb systems. In such so-called complex plasmas structure formation can be observed, from crystalline states (`plasma crystal') to dynamical fluids, depending on the plasma parameters. Since gravity is a disturbing factor many experiments with complex plasmas are performed in microgravity, e.g. on parabolic flights or aboard the International Space Station ISS.
We report here on experiments on so-called electro-rheological (ER) plasmas done on parabolic flights. ER plasmas are a model system of well-known and technically used ER fluids where immersed particles form strings when an electric field is applied. This drastically changes rheological properties, such as viscosity and elasticity of the fluid.
In a setup similar to PK-4 on the ISS we use a laser to manipulate strings of microparticles inside a polarity-switched DC discharge by applying a force (light pressure) in longitudinal as well as transversal direction. The behaviour between particles in strings and unbound particles is investigated to compare their rheology and to decide whether the labeling of a complex plasma as `ER' is justified.