IPP Director Per Helander receives the Alfvén Prize

Every year, the European Physical Society (EPS) honours researchers for outstanding achievements in the field of plasma physics with the Hannes Alfvén Prize. Prof Dr Per Helander from the Max Planck Institute for Plasma Physics (IPP) is one of the two laureates for 2024.

Per Helander has headed the Stellarator Theory department at the IPP in Greifswald since 2006 and holds the Chair of Theoretical Plasma Physics at the University of Greifswald. The EPS is awarding him the Hannes Alfvén Prize together with his colleague Prof Dr Tünde Fülöp. Prof Helander and Prof Fülöp have made fundamental contributions to plasma theory, writes the EPS in its tribute to the award winners.

The two Swedish researchers have known each other since their time at Chalmers University of Technology in Sweden, where Prof Fülöp still works today. Both are theoretical physicists and also published joint papers during this time. However, while Prof. Helander increasingly focused on stellarators, Prof. Fülöp specialised in the second concept for realising fusion power plants with magnetic confinement - the tokamak. "I tried in vain to get Tünde excited about stellarators," jokes Prof Helander today.

Calculations that explain the success of Wendelstein 7-X

He himself carried out calculations that provided valuable insights into the operation of stellarators such as Wendelstein 7-X at the IPP in Greifswald. Prof Helander investigated how the geometry of the magnetic fields affects the properties of the enclosed plasma. He focussed in particular on the biggest problem in plasma physics - turbulence. It leads to undesirable energy losses in the plasma. However, if this can be brought under control, smaller and more cost-effective devices could be built.

Prof Helander and his collaborators predicted that one of the most important instability phenomena will disappear if steep density profiles can be generated in the plasma if the magnetic field possesses certain properties. This effect is probably one reason for record plasma performance achieved in Wendelstein 7-X in recent years. The necessary density profiles are generated there by injecting hydrogen pellets.

The most important tools: pen and paper

Prof Helander gains physical insights primarily by analytical means: "My most important tools have always been pen and paper," he says. In his early days he sometimes wrote simple computer codes to tackle physical problems numerically. "Both methods are of great value," explains Prof Helander. "Most problems can only be solved numerically, but I find that analytical methods can lead to a deeper understanding of phenomena." In his IPP department in Greifswald, the two methods are closely interlinked. Stellarator optimisation only works by carrying out complex calculations on supercomputers. "But analytic considerations show in which direction we should steer the calculations so that they deliver the desired result."

He cooperates with start-ups, but sees himself primarily as a natural scientist

Calculations of this kind are essential in order to develop commercial fusion power plants from today's stellarator experiments. This is why Prof Helander and his department are also important partners for start-up companies that want to follow this path. He himself is always driven by the desire to get to the bottom of things: "I am a natural scientist. I want us to be able to simulate plasmas in the computer but also to understand them with our human brains.”

The EPS will award the Alfvén Prize at its 50th Conference on Plasma Physics on 8 July 2024 in Salamanca, Spain. The prize is endowed with a total of 5000 euros.

Announcement from EPS: http://plasma.ciemat.es/eps/