Archived highlights from the division Stellarator Edge and Divertor Physics (E4)
Measuring the magnetic flux surfaces of Wendelstein 7-X
The division E4 is operating a diagnostic which allows an accurate determination of the flux surfaces of Wendelstein 7-X. It works by emitting a thin filament of energetic electrons into the magnetic field. This current will trace the magnet field lines, while exciting visible fluorescence radiation in some molecules of the residual background gas. Thus, the magnetic field lines become 'visible'. First experiments yielded an excellent verification of the magnetic field calculations done beforehand.
For more information see the press release.
Injection of positrons into the field of a permanent magnet
In order to produce a magnetically confined pair plasma from electrons and positrons, positrons have to enter the magnetic confinement region from the outside. The PAX/APEX team reached this important milestone in a joint experiment with the positron group from TU Munich. Positrons from the NEPOMUC beamline at the FRM II research reactor in Garching where steered into the field of a permanent magnet. Up to almost 40 % of the initial particles were able to enter this field, and were stored there for on the order of 5 ms.
Results were published in 'New Journal of Physics', granting open access to all.