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TOWARD A NEXT GENERATION SOLAR CORONAGRAPH: DIFFRACTED LIGHT SIMULATION AND TEST RESULTS FOR A CONE OCCULTER WITH TAPERED SURFACE KCI 등재 SCOPUS
- 언어ENG
- URLhttps://db.koreascholar.com/Article/Detail/383925
pp.27-36
In a solar coronagraph, the most important component is an occulter to block the direct light from the disk of the sun. Because the intensity of the solar outer corona is 10−6 to 10−10 times of that of the solar disk (I⊙), it is necessary to minimize scattering at the optical elements and diffraction at the occulter. Using a Fourier optic simulation and a stray light test, we investigated the performance of a compact coronagraph that uses an external truncated-cone occulter without an internal occulter and Lyot stop. In the simulation, the diffracted light was minimized to the order of 7.6 × 10−10 I⊙ when the cone angle c was about 0.39◦. The performance of the cone occulter was then tested by experiment. The level of the diffracted light reached the order of 6 × 10−9 I⊙ at c = 0.40◦. This is sufficient to observe the outer corona without additional optical elements such as a Lyot stop or inner occulter. We also found the manufacturing tolerance of the cone angle to be 0.05◦, the lateral alignment tolerance was 45 μm, and the angular alignment tolerance was 0.043◦. Our results suggest that the physical size of coronagraphs can be shortened significantly by using a cone occulter.
1. INTRODUCTION
2. FOURIER OPTICS SIMULATION USING GLAD
2.1. Specification of the Simulation
2.2. Simulation Results
3. DIFFRACTED LIGHT TEST IN DARK TUNNEL
3.1. Experiment Result
4. SUMMARY AND CONCLUSION
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