The first official plasma has been obtained in Wendelstein 7-X today at 2015-12-10T12:28:15.182965421Z in the official W7-X time base. We participated remotely in the inauguration ceremony and could feel the excitement of all people involved on this truly historic step in fusion sciences. Congratulations to the entire Wendelstein 7-X team on this monumental step.
We participate on the device with several diagnostic projects and a numerical study on plasma edge transport. The diagnostics which the graduate students L. Stephey and T. Kremeyer prepared in the past year and intensively during long term research visits this summer took data during the first plasma. Below a plot of the neutral pressure in the plasma periphery measured with the UW Madison Penning gauge at W7-X is shown. This is a collaborative project with IPP Greifswald and Dr. Uwe Wenzel was visiting this week for detailed discussionson the next steps in the project and also for a visit to our vacuum laboratory in which we prepare this diagnostic component for W7-X. RA T. Kremeyer is responsible for this project and he will conduct his PhD research on neutral gas dynamics and plasma fueling at W7-X. This work is funded by the Department of Energy under grant DE-SC0014210.
RA L. Stephey from the HSX Laboratory in the Department for Electrical and Computer Engineering works under this grant to measure limiter heat and particle fluxes at W7-X and establish a single reservoir particle balance. A first image from the first plasma at W7-X taken with a CCD camera with a filter which L. Stephey initialized and activated for measurements is shown below. It shows the plasma column in front of the limiter at the inner side of the vacuum vessel. This activity is a close collaboration with Dr. G. Wurden from the Los Alamos National Laboratory. L. Stephey is also responsible for on-site maintenance and operation of an Oak Ridge Filter Scope system. Both systems and supplemental general diagnostics will be the basis to assess the W7-X particle balance and make direct comparisons to HSX.
We are excited to be part of the U.S. team working on W7-X and look forward to fruitful and exciting physics studies on this unique device.