| Autor: |
M. R. Major, G. R. McKee, B. Geiger, D. J. Den Hartog, K. Jaehnig, C. Seyfert, D. R. Smith, S. D. Stewart, Z. Yan |
| Rok vydání: |
2022 |
| Předmět: |
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| Zdroj: |
The Review of scientific instruments. 93(11) |
| ISSN: |
1089-7623 |
| Popis: |
A new high radial resolution 2D multichannel Charge eXchange Imaging (CXI) diagnostic is under development for deployment at DIII-D. The diagnostic system will measure low-to-intermediate radial wavenumber carbon density fluctuations by observing the n = 8 − 7 ( λ = 529.06 nm) C-VI emission line, resulting from charge exchange collisions between heating neutral beam atoms and the intrinsic carbon ion density. The new CXI diagnostic will provide measurements with Δ R ∼ 0.4 cm to access higher k r instabilities ( k r < 8 cm−1) predicted to arise in the steep-gradient region of the H-mode pedestal. The CXI system will feature 60 fiber bundles in a 12 × 5 arrangement, with each bundle consisting of four 1 mm fibers. A custom optical system has been designed to filter and image incoming signals onto an 8 × 8 avalanche photodiode array. Additionally, a novel electronics suite has been designed and commissioned to amplify and digitize the relatively low-intensity carbon signal at a 2 MHz bandwidth. Forward modeling results of the active C-VI emission suggest sufficient signal to noise ratios to resolve turbulent fluctuations. Prototype measurements demonstrate the ability to perform high frequency pedestal measurements. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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