Nuclear fusion involves the fusion of light atomic nuclei to form a heavier nucleus that weighs less than the sum of the two light nuclei. According to Einstein's famous formula E=mc², the difference in mass is released as energy. This energy can be harnessed to drive a turbine, for example, to generate electricity.
One challenge with nuclear fusion is turbulence, which causes losses of particles and heat. In order to understand and control these processes, comprehensive comparative work of large experiments with corresponding numerical tools is essential. In a new study, experiments at the ASDEX Upgrade fusion experiment at the Max Planck Institute for Plasma Physics in Garching were compared with simulations of the GENE code developed at the same institute.
Diagnostics play a decisive role in such a comparison. In the experiment, microwaves are injected into the plasma and scattered and reflected by turbulent plasma density structures. An analysis of the reflected microwave allows to draw conclusions about the turbulence. A quantitative comparison with simulations is only possible if the simulations are examined with diagnostics corresponding to the experiment. Dr. Carsten Lechte from IGVP developed such a code, IPF-FD3D, which radiates microwaves into the plasma, provided by the turbulence code GENE, and then examines the reflected microwaves, just as in the experiment. This code enabled comparisons to be made to an unprecedented degree of the turbulence in the ASDEX upgrade with the turbulence generated by GENE. The results are now published in Nature Communications and allow a better understanding of the control of turbulence and are thus an important step towards a fusion power plant.
