PHOTON SCIENCE

A research team comprising of scientists from DESY, the University of Hamburg, Helmholtz-Zentrum Dresden-Rossendorf, the University of Rostock and the Fraunhofer Institute for Laser Technology have been awarded a 14 million euro grant for the project IFuEL (short for Inertial Fusion Energy Laser Development and HED-Analytics). The project focuses on the development and testing of a highly efficient and scalable laser technology for fusion research. The grant is part of the Fusion 2040 programme of the German Federal Ministry of Research, Technology, and Space (BMFTR) and will concentrate on a promising avenue in fusion energy research: inertial confinement fusion. The laser technology made possible through this grant will also be used for fusion-relevant material science at DESY’s PETRA III light source and its future upgrade, PETRA IV.

Inertial confinement fusion (ICF) has become a major topic since the groundbreaking 2022 experiment at the National Ignition Facility in the United States. That experiment used extremely high-energy lasers to compress two heavier versions of hydrogen, deuterium and tritium in such a way as to initiate fusion, the process that powers the sun and other stars. The 2022 experiment was the first ever demonstration of fusion where the power output was greater than the input.

Initiated in response to this finding, the BMFTR’s Fusion 2040 research programme aim, among other objectives, to establish the necessary scientific and technological infrastructure for inertial laser fusion as a step towards the development of a prototype fusion reactor in Germany within the next two decades.

“Making ICF a viable and sustainable energy source in the future depends critically on our ability to build highly efficient, high-energy laser systems that can operate at much higher repetition rates than today’s lasers”, says Franz Kärtner, principal investigator of the IFuEL project, a lead scientist at DESY and a professor of physics at the University of Hamburg. “This is where IFuEL will contribute through the expertise and technical know-how we’ve gained over a long period of time.”

For a laser system intended for use in a future ICF power plant, novel laser technology is essential. For many years, Kärtner’s group has been developing lasers based on the use of cryogenically cooled Yb:YLF crystals, supported by the ERC Synergy Grant AXSIS and the University of Hamburg Cluster of Excellence CUI: Advanced Imaging of Matter (AIM). The Yb:YLF laser technology has the potential to double the efficiency of alternative high-energy and high-power laser technologies while lowering costs by around a factor of 10.

“The grant from the BMFTR will help us show that we can build a 200 joule Yb:YLF laser, the sort of which could serve as a building block for a much larger laser system in an ICF power plant,” says Mikhail Pergament, head of the laser science and technology development in Kärtner’s group. “While we are already operating similarly powered Yb:YLF laser systems, the key challenge in IFuEL is to simultaneously demonstrate that we can generate 100-joule-class pulses with high power efficiency in a scalable fashion with an eye on enabling fusion-grade pulse energies in the million-joule range in the future.”

In addition to developing the laser, the team will test it in fusion-relevant materials at all of the partner institutes. The team will build a high-intensity laser–matter interaction chamber at DESY that will house a hydrogen jet which will be the target for the laser. Parts of the beam transport system that will direct the laser to the hydrogen jet will be developed and constructed by HZDR, a fellow Helmholtz research centre. HZDR has longstanding experience in the operation of high-power lasers and cryojet experiments at their laser facility DRACO and at the European XFEL. Researchers from the University of Rostock will characterise the plasma and its associated ion showers created when the laser meets the hydrogen jet. The team will use the plasma analysis to test potential materials for a prototype fusion reactor’s wall.

Using PETRA III and DESY’s NanoLab, the DESY Photon Science team will evaluate various reactor wall materials under fusion-relevant conditions. The high durability of such materials, called plasma-facing materials (PFM), would be essential to the viability of a fusion reactor. “This new platform for the testing of existing as well as novel PFM to ions released from the plasma would make DESY one of the future test facilities contributing to the fusion research ecosystem that the BMFTR is establishing in Germany”, says Hanns-Peter Liermann, beamline scientist in charge of the Extreme Conditions Beamline at PETRA III.

Hauke Heekeren, President of the University of Hamburg, says: “The IFuEL project is a powerful example of how our University of Excellence, together with DESY and strong partners from the Helmholtz Association and applied research, is tackling some of the most fundamental technological challenges of the future. By developing highly efficient laser systems for fusion research, we are making an important contribution to the path toward sustainable energy supply and enhancing the international visibility of Hamburg as a leading centre of science.”

“This exciting new project makes excellent use of DESY’s strength in photon science, from the development of new laser technologies to the research centre’s analytical capabilities at PETRA III and at the future PETRA IV,” says Britta Redlich, Director in charge of DESY Photon Science.

The project will also strengthen the DESY role in the recently announced Fusion Alliance, where the German federal states of Hamburg and Schleswig-Holstein, alongside DESY and European XFEL, partnered with four other federal states on fusion research. Beate Heinemann, Chair of the DESY Directorate, says: “DESY can make significant contributions in developing technologies towards laser-based fusion – and, thanks to the funding by the BMFTR, IFuEL will now enable this.”


(Partly from DESY News)