06/30/2026

Sebastian “Tiano” Haag has been a technician in our research group since May 2022. He played a key role in the reconstruction and recommissioning of the VINETA experiment. He has supported us with all our work in the laboratory. Particularly noteworthy is the development and construction of a control cabinet for our planned small tokamak experiment and the axial movement unit for VINETA. He has done a truly outstanding job. We will miss him very much. All the best.

06/27/2026

At Science Day, Peter Manz, Franz Bronold and Sebastian Haag demonstrated how extremely hot gas (plasma) can be confined without contact by complex magnetic fields. The mini-stellarator makes the fundamentals of magnetic plasma confinement tangible for young and old alike. Unlike its larger counterpart, the Wendelstein 7-X, the mini-stellarator is designed to be handled directly. Science Day was a resounding success for us. We were delighted to welcome everyone who visited us on Saturday.  
The mini-stellarator was developed and built at the IPP; we would like to thank the IPP for the donation. 

06/26/2026

At the RIAM Forum, Peter Manz presented our study on the transition into turbulence.

Turbulence is one of the most fundamental and challenging phenomena in fluid and plasma physics. In magnetically confined plasmas, turbulence is responsible for strong particle and heat transport and therefore plays an important role for fusion research. While fully developed turbulence has been studied extensively, considerably less is known about transitional regimes between ordered wave dynamics and broadband turbulence. Similar questions also arise in neutral-fluid flows, where localized turbulent structures, known as puffs and slugs, appear close to the transition to turbulence in pipe flows.

In this work, we investigate transitional drift-wave turbulence in the linear magnetized plasma experiment PANTA. Drift waves are among the most fundamental plasma instabilities and provide a comparatively simple system for studying the onset of turbulent behavior in magnetized plasmas. By varying the magnetic-field strength, the plasma dynamics change from relatively coherent wave motion to increasingly irregular turbulent states.

The experiments reveal the appearance of long-lived coherent structures that show remarkable similarities to puffs and slugs known from transitional pipe flows. Using conditional-averaging techniques, the temporal evolution of these structures can be followed over long timescales. Near the transitional regime, the structures persist much longer than expected from conventional local correlation measurements. Small changes of magnetic-field strength lead to strong changes in the correlation times and correlation lengths, indicating the existence of a critical point associated with a nonequilibrium phase transition.

Different dynamical behaviors are observed depending on the magnetic-field strength. At lower magnetic field, coherent structures occasionally split into smaller daughter structures in a process similar to puff splitting in pipe flows. At intermediate magnetic field, expanding coherent structures resembling slugs are observed, followed by the formation of gaps that separate the structures into multiple parts. At higher magnetic field, several coherent structures coexist and interact strongly with each other, leading to a behavior comparable to puff jamming. In this regime, the interaction between structures shortens their lifetime and enhances the transition toward broadband turbulence.

The results demonstrate that important concepts from transitional turbulence in neutral fluids can also appear in magnetized plasmas despite the very different physical environments. In particular, the experiments suggest that transitional drift-wave turbulence may be governed by universal mechanisms related to self-sustained turbulence and nonequilibrium phase transitions. These findings open new perspectives for understanding the emergence and regulation of turbulence in plasmas and may contribute to a deeper connection between plasma physics and modern fluid dynamics.

This study has been published in Phys. Rev. E. 

On 19 and 20 May, we held the kick-off meeting for the DYNAFLUC project in Paris. The project brings together many researchers with diverse areas of expertise and perspectives. Peter Manz and Sander De Koker presented their joint project. There were many interesting discussions. We would like to thank Laure Vermare for organising the event.