27.11.2020 Vortrag bei der Nacht der Wissenschaft

Alles Plasma, der vierte Aggregatzustand

21.10.2020 New  Project "Towards a new method to measure low energy electron sticking coefficients using dusty plasmas"  funded by DFG

The theoretical description of the plasma surface interface is a challenging task. F. Bronold from the University of Greifwald developed the ’Invariant embedding approach’ (IEA)  that opens the door to a new method for the determination of low energy electron sticking coefficients ( in a dusty plasma. Bronolds theory in combination with high precision methods for the determination of the charge to mass ratio  of micron sized grains embedded in a low-temperature plasma,  developed at the "Experimental plasma physics group" at IEAP/CAU  are the ingredients of the proposal of Franko Greiner  "Towards a new method to measure low energy electron sticking coefficients using dusty plasmas".  

The DFG reviewers ranked the proposal as " perfectly scientifically sound",  "excellent"  and "very timely in the more-and-more recognized field of plasma-surface interaction".  The reviewers explicitly mentioned the CAU as"one of the foremost and advanced centers for research into dusty plasma physics" and emphasized the impact that this research environment will have on the project.  We are very happy that F. Bronold  has agreed to critically  accompany the project from the theoretical side.

The figure shows the direction cosines ξ and electron energy E resolved prediction of the electron sticking coefficient calculated by IEA (a) and its comparison with one of the few published experimental results for MgO (b). See the above mentioned publication for more details.

Prediction of the electron sticking coefficient calculated by IEA and its comparison with one of the few published experimental results for MgO.


4.12.2019: Entropy measurements published in PRL

In the framework of the DFG project BL555 3-1, Frank Wieben and Dietmar Block managed to explore basic thermodynamic properties of complex plasmas and especially binary mixtures. In the recent issue of PRL ( they report on successful direct measurements of entropy and its change during heating and cooling. Although entropy is one of the most fundamental quantities in thermodynamics, its direct measurement is impossible in most systems. Using two-dimensional plasma crystals, a sophisticated laser heating mechanism to heat these crystals without melting and high precision particle tracking to measure the full phase space allowed to study the change of entropy in a heating and cooling experiment. It turned out that these systems strictly follow the laws of thermodynamics even if mixtures of different particles are used. The results show on the one hand side that complex plasmas are a model system for strongly coupled systems even with respect to thermodynamic properties and on the other hand side that fundamental studies of systems with non-Maxwellian distributions should be feasible.


22.08.2019: 1.1 Mill. Euro funding for research on interaction of plasma with nano- and microparticles

Three new DFG projects approved for funding in the last three months.

The group members have successfully applied for funding by the German Science Foundation (DFG). Three project proposals investigating the behavior of micro- and nanoparticles in plasmas have successfully applied for funding: Prof. Jan Benedikt with the project In situ analysis of plasma-induced material modifications on nanoparticles for functional applications, Prof. Dietmar Block with the project Size and Morphology Changes of Microparticles in plasmas and Dr. Franko Greiner with the proposal Dusty plasmas with high electron depletion: investigation of fundamental mechanisms. Altogether, five PhD positions and almost 1,1 Million Euro, partially in collaboration with the groups of Prof. Franz Faupel at the Engineering Faculty and Prof. Sebastian Wolf at the Institute of Theoretical Physics and Astrophysics, are dedicated to this research. These joint activities are part of the KiNSIS initiative at Kiel university.

Doctoral candidate Oguz Han Asnaz at his plasma chamber for the production and treatment of nanoparticles.

15.06.2019: 24th ISPC conference in Naples

From 11 to 14 June the 24th International Symposium on Plasma Chemistry (ISPC) took place in Naples, Italy. The Experimental Plasmaphysics group was also represented by a group of three people. Jan Benedikt gave a talk on "Atmospheric plasma jets for generation of nanostructured materials or nanoparticles". Kerstin Sgonina presented her work on "Interaction of plasma-generated reactive oxygen species with aqueous solutions". Judith Golda also presented her results on "Analyzing plasma-chemical processes in RF-excited atmospheric pressure plasmas using VUV and visible optical emission spectroscopy".

17.04.2019:  Editor's Pick in Physics of Plasmas

A micro-particle exposed to  a plasma may change size and morphology.  This can be studied in great detail by analyzing light scattered by the micro-particle.  During his master thesis  Nklas Kohlmamn developed a method which uses the angle and polarization resolved light scattered by the particle for high precision size measurements. He demonstrated a resolution as low as one nanometer.  The  paper was (Plasmas 26, 053701 (2019))  now picked by the editors of Physics of Plasmas to be promoted as an Editor's Pick.Mie Scattering Setup for high precission size measurements




16.04.2019: Visit from the Czech Academi of Sciences in Prag in the frame of DAAD project

The group has been visited by Dr. Katerina Herynkova, Dr. MArtin Müller and Dr. Pabel Galar from the Czech Academi of Sciences, Institute of Physics, in the frame of the DAAD project (2019-2020) Monodisperse direct-bandgap silicon nanoparticles for advanced optoelectronic and biological applications. The researchers have participated on the generation of silicon nanoparticles by means of atmospheric and low-pressure plasmas. Dr. Pavel Galar gave a talk with the title Applications of non-thermal plasmas: synthesis and modifications of nanostractures (see Photograph). 

Dr. Galar during his talk.


04.03.2019:  Editor's Pick in Physics of Plasmas

What happens with particles in a plasma which are exposed to intense laser radiation? The answer is given by Frank Wieben, Jan Schablinski and Dietmar Block in their recent publication in Physics of Plasmas. In their experiments the dynamic response of a microparticle, which is first trapped in an intense laser beam (optical tweezers) and then de-trapped, is compared to a reference particle in close vicinity. The data clearly shows that the particle charge changes and this is most likely due to an increase in particle size. However, the astonishing part of the results is that the particle size increases far more than it could be expected from pure thermal expansion and that this process is fully reversible. These findings have some importnat implications for future experiments. First, they offer a possibility to gain further insight into plasma surface interaction. Second, they show that optical tweezers can be used without changing the particle properties permanently, which plays a keyrole for all structural and dynamical manipulations of dusty plasmas with optical tweezers. The fact that the American Institut of Physics has selected the work as an important contribution in the field of  plasma physics and highlights it as an Editor's Pick in the journal Physics of Plasmas is a special honor.

levitation height and its change as soon as the laser is switched off

19.02.2019:  Tutorial published in Journal of Physics B

Journal of Physics B has published today a tutorial entitled 'Dusty (Complex) Plasmas - routes towards magnetized and polydisperse systems' by Dietmar Block and Andre Melzer. The tutorial covers recent developments in the field of dusty (complex) plasmas. After a brief summary of fundamental concepts, its focus is on novel diagnostics in dusty plasmas which have proven to be important tools on the route towards studying magnetized and polydisperse dust systems. These two hot topics of dusty (complex) plasma research are introduced from an experimentalists view. The tutorial summarizes the current understanding and adresses open questions in both reseach foci. It is accessible online at

04.01.2019:   DAAD Mobility project approved 

Deutscher Akademischer Austauschdienst (DAAD) has approved two years mobility project of the group with the Institute of Physics of the Czech Academy of Sciences in Prague with the title Monodisperse direct-bandgap silicon nanoparticles for advanced optoelectronic and biological applications. Visits of scientists and young researchers from both institutions will be funded to investigate the plasma-based generation of silicon nanoparticles (Kiel) and their optoelectronic properties and interaction with biological substrates. RNDr. Kateřina Herynková is the principal investigator responsible for the research at the Department of Thin Films and Nanostructures of the Czech Academy of Sciences.

26.12.2018:   Photophoretic force measruement published in Physics of Plasmas

Frank Wieben and Dietmar Block published their recent work on binary mixtures in Physics of Plasmas (download).  The article presents a method to measure quantitatively for the first time the photophoretic force on microparticles in a complex plasma. A laser heating setup is used to increase the kinetic temperatures of binary mixtures composed of melamine-formaldehyde (MF) and silica (SiO2) particles. The temperature gain of both particle species due to the additional thermal reservoir is compared to a laser force model. Contributions of radiation pressure and photophoretic forces are determined through a variation of neutral gas pressure and application of Lorenz-Mie theory. The photophoretic force is found to be significant for MF particles at typical conditions in complex plasma experiments. This research is part of the DFG project BL555-3.

20.12.2018:   Tim Donders, physics student  at Eindhoven University,  finshed  internship

From September to December 2018, Tim Donders, a master student in the friendly  group of Job Beckers at Einhoven University of Technology, successfully completed an intership in Kiel. He performed  two dimensional  measurements with electrostatic probes and  video diagnostic of nanodusty plasmas. One focus was the investigation of filaments in  the magnetized plasma of a CCP.  The traces of the filaments in a nanodust cloud (see image)  can be used to  learn about the  scaling of the filaments with the magnetic field.

 Tim and Dustwheel


25.06.2018: The Best Student Paper Award for Kerstin Sgonina at the 7th International Conference on Plasma Medicine in Philadelphia

Kerstin Sgonina, Ph.D. candidate working on the DFG funded project Cold atmospheric plasmas for the study of fundamental interaction mechanisms with biological substrates: the role of ions and the plasma-induced liquid chemistry, has received The Best Student Paper Award at the 7th International Conference on Plasma Medicine in Philadelphia for her poster Investigation of the Isolated Ion Interaction with Biological Substrates and Liquids. Congratulation!



19.04.2018: New publication

The paper focuses on the reaction mechanisms of plasma-generated oxygen atoms in aqueous solutions. The effluent from a plasma source operated with standard and 18O-labeled O2 gas was used to treat water in the presence of phenol as a chemical probe. Comparing mass spectrometry and gas chromatography-mass spectrometry data of the solutions treated with plasma under normal and labeled oxygen provides clear evidence that O(aq) originating from the gas phase enters the liquid and reacts directly with phenol, without any intermediate reactions. Additionally, the atmospheric-pressure plasma source demonstrates great potential to be an effective source of O(aq) atoms without the requirement for any precursors in the liquid phase.

The fate of plasma-generated oxygen atoms in aqueous solutions

The fate of plasma-generated oxygen atoms in aqueous solutions.




09.03.2018: DPG spring meeting in Erlangen

On Monday, 5th March 2018, the 82nd DPG Spring Meeting started in Erlangen. For four days, scientists from all over Germany met to discuss their latest results on atomic, molecular, plasma physics, and quantum optics.The AG Benedikt from Kiel University also joined the meeting with four poster presentations and seven oral contributions. 

DPG spring meeting 2018


Scientific visit

Dr. Kateřina Herynková, Martin Müller and Dr. Ondrej E. Cibulka from the Department of Thin Films and Nanostructures, Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic visited in November 2017 Prof. Dr. Jan Benedikt (DAAD Project Atmospheric plasma-based generation of silicon nanocrystals for future energy applications). Dr. Herynková gave a lecture with the title "Luminescing silicon nanoparticles for optoelectronic and biological applications".

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