Design criteria of the bolometer diagnostic for steady-state operation of the W7-X stellarator

A bolometric diagnostic system with features necessary for steady-state operation in the superconducting stellarator W7-X was designed. During a pulse length of 1800 s with an ECRH (electron cyclotron resonance heating) power of 10 MW, the components suffer not only from a large thermal load but also from stray radiation of the nonabsorbed isotropic microwaves. This paper gives an overview of the technical problems encountered during the design work and the solutions to individual problems to meet the special requirements in W7-X, e.g., component thermal protection, detector offset thermal drift suppression, as well as a microwave shielding technique. © 2010 American Institute of Physic

Navigating Haystacks at 70 mph: Intelligent Search for Intelligent In-Car Services

ABSTRACT With an explosion of in-car services, it has become not only difficult but unsafe for drivers to search and access large amounts of information using current interaction paradigms. In this paper, we present a novel approach for visualizing and exploring search results, and the potential benefits of its application to the current in-car environment. We have iteratively developed and tested a prototype system that enables the seamless and personalized exploration of information spaces. In a number of eye-tracking studies, we analyzed user satisfaction and task performance for factual and explorative search tasks. We found that most participants were faster, made fewer errors and found the system easier to use than traditional ones. We believe that this approach would improve the traditional in-car interfaces -to search and access large number of services with rich information. This would reduce driver inattention to the road and improve road safety

Searching for O-X-B mode-conversion window with monitoring of stray microwave radiation in LHD

In the Large Helical Device, the stray microwave radiation is monitored by using so-called sniffer probes during electron cyclotron heating. In monitoring the stray radiation, we changed the microwave beam injection angle and search the O-X-B mode-conversion window to excite electron Bernstein waves (EBWs). When the microwave beam is injected toward the vicinity of the predicted O-X-B mode-conversion window, the electron temperature rises in the central part of overdense plasmas. In that case, the stray radiation level near the injection antenna becomes low. These results indicate that monitoring the stray radiation near the injection antenna is helpful in confirming the effectiveness of excitation of EBWs simply without precise analysis