Title
Thermo-mechanical behavior of retro-reflector and resulting parallelism error of laser beams for Wendelstein 7-X interferometer
Author
Peng, X.B.
Hirsch, M.
Köppen, M.
Fellinger, J.
Bykov, V.
Schauer, F.
Vliegenthart, W.A.
Publication year
2014
Abstract
A 10 channels interferometer will be used in the Wendelstein 7-X (W7-X) for plasma density control and density profile tracking with laser beams passing through the plasma. Due to complex shape of non-planar modular coils and divertor structure, there are no large poloidally opposite ports on the plasma vessel (PV). Therefore 10 in-vessel Corner Cube Retro-reflectors (CCRs) will be used. The CCRs are integrated in the water cooled heat shield and exposed directly to thermal loads from plasma radiation. Thermo-mechanical issues are very important for the design of the CCR because deformation and flatness as well as mutual angles of the three reflecting surfaces would affect the parallelism of the laser beams and the functionality of the interferometer. Intensive work has been done to explore a suitable design for the CCR concerning thermo-mechanical behavior. Previous studies Ye et al. (2008, 2009) and Köppen et al. (2011) focused on structural optimization to decrease thermal stress in the reflecting plates under the thermal loads, and on computation and check of curvature radii of the deformed reflecting surfaces with the design criterion that the curvature radius must be bigger than 200 m. The paper presents detailed thermo-mechanical analysis of the current improved CCR under thermal loads and bolt preloads. The results of the thermo-mechanical analysis were used for the study of the resulting parallelism error of the laser beams with newly developed and more reasonable design criterion. © 2014 Elsevier B.V.
Subject
Physics & Electronics
SSE - Space Systems Engineering
TS - Technical Sciences
Space
Information Society
Parallelism
Retro-reflector
W7-X
Interferometers
Plasma density
Thermal load
Corner cube retro-reflectors
Reflecting surface
Thermo-mechanical analysis
Thermo-mechanical behaviors
Laser beams
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http://resolver.tudelft.nl/uuid:3a976dd9-5f18-445a-b0b7-d56725ebfc35
TNO identifier
507148
Publisher
Elsevier, Amsterdam
ISSN
0920-3796
Source
Fusion Engineering and Design, 89 (4), 318-323
Document type
article