Towards a new image processing system at Wendelstein 7-X: From spatial calibration to characterization of thermal events

Wendelstein 7-X (W7-X) is the most advanced fusion experiment in the stellarator line and is aimed at proving that the stellarator concept is suitable for a fusion reactor. One of the most important issues for fusion reactors is the monitoring of plasma facing components when exposed to very high heat loads, through the use of visible and infrared (IR) cameras. In this paper, a new image processing system for the analysis of the strike lines on the inboard limiters from the first W7-X experimental campaign is presented. This system builds a model of the IR cameras through the use of spatial calibration techniques, helping to characterize the strike lines by using the information given by real spatial coordinates of each pixel. The characterization of the strike lines is made in terms of position, size, and shape, after projecting the camera image in a 2D grid which tries to preserve the curvilinear surface distances between points. The description of the strike-line shape is made by means of the Fourier Descriptors

Forward modeling of collective Thomson scattering for Wendelstein 7-X plasmas: Electrostatic approximation

In this paper, we present a method for numerical computation of collective Thomson scattering (CTS). We developed a forward model, eCTS, in the electrostatic approximation and benchmarked it against a full electromagnetic model. Differences between the electrostatic and the electromagnetic models are discussed. The sensitivity of the results to the ion temperature and the plasma composition is demonstrated. We integrated the model into the Bayesian data analysis framework Minerva and used it for the analysis of noisy synthetic data sets produced by a full electromagnetic model. It is shown that eCTS can be used for the inference of the bulk ion temperature. The model has been used to infer the bulk ion temperature from the first CTS measurements on Wendelstein 7-X

The wheelchair ergometer for adjustments in manual wheelchair use in action!

Wheelchair ergometer Obtaining objective propulsion data to analyze the interface of user and wheelchair in action to contribute to the advice for adjustments. Active lifestyle A well-adjusted wheelchair can contribute to an active lifestyle, maximal participation in society and avoiding overload. Current status Protocol consisted of 30s sprint, driving at comfortable speed and maintaining given constant speed

Design aspects of the joints for the bus bar system of the Wendelstein 7-X stellarator

The superconducting magnet system of the Wendelstein 7-X experiment consists of 50 non-planar and 20 planar coils. The coils are connected by 121 bus bars arranged in a series of seven groups each of 10 coils. The electrical and hydraulical interconnections of the bus bars will be provided by means of 184 joints each with the required resistance of less than 5 nΩ. The joint structure should withstand the internal pressure arising from the quench event. In order to permit joint replacement and repair after installation the joints have to be designed as demountable structures. Based on a conceptual design for an internal pressure of 30 bar and a current of 18 kA, the disconnectable joints have been redesigned for a pressure of 200 bar and a current of 20 kA. The report describes design, tests and stress analysis