Note: Real-time wavelength matching system designed for the motional Stark effect polarimeter on HL-2A tokamak
| Autor: | Y. L. Wei, Qingwei Yang, Wei Chen, Yaohua Liu, X X He, B S Yuan, Longwen Yan, Zhongbing Shi, Ling Liu, Jin Wang, D. L. Yu |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Tokamak business.industry Polarimeter Polarization (waves) 01 natural sciences 010305 fluids & plasmas law.invention symbols.namesake Wavelength Optics Stark effect law Temporal resolution 0103 physical sciences symbols Physics::Accelerator Physics Plasma diagnostics 010306 general physics business Instrumentation Doppler effect |
| Zdroj: | Review of Scientific Instruments. 89:126103 |
| ISSN: | 1089-7623 0034-6748 |
| Popis: | A 7-channel motional Stark effect diagnostic based on dual photo-elastic modulators is installed and operated routinely for rather low beam energy and magnetic field on the HL-2A tokamak, with a spatial resolution of ∼3 cm and a temporal resolution of 10 ms. The instrument observes the σ component of the full energy Dα from the first or the fourth ion source of a neutral beam injector. However, the change in beam energy during a discharge causes variation of the Doppler shift with the maximum of 1 A, which leads to the polarization fraction drop from 30%-40% to 10% and then makes the signal-to-noise ratio of the system become very poor. Therefore, a real-time wavelength matching system is designed to promote polarization fraction. The beam emission spectra are filtered by using a monochrometer in real time. And a narrowband filter is tilted by using an absolutely calibrated rotator through beam energy in order to make sure that the deviation of wavelength matching is less than 0.1 A. |
| Databáze: | OpenAIRE |
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