Development of an Adaptive Optics System for the Solar Observation

研究太阳大气中发生的各种活动现象在科学上是非常重要的，因为它们是恒星大气中的基本现象，而且它们显示了在实验室中无法重现的等离子体现象，而且它们对地球的等离子体环境影响很大。要研究这种活动现象，以高空间分辨率观测太阳表面结构至关重要。自适应光学是实现地基观测高分辨率的关键技术。为了在不久的将来用1米级望远镜实现衍射极限分辨率的观测，我们正在研制一种太阳观测自适应光学系统。首先设计了自适应光学系统的总体结构，并引入了波前控制的关键器件——可变形镜。通过实验得到了变形镜的控制参数，建立了对变形镜施加的控制信号与干涉仪测量到的相应波前变化之间的关系。由于波前的实际计算和镜面的控制需要高速（每秒几百个周期），我们开发了一个高速实时软件。最后我们完成了系统的集成。我们将我们的系统连接到京都飞驒天文台的无穹顶太阳望远镜上，这是一个60厘米的太阳望远镜，用真实的太阳图像来测试系统。不幸的是，有时我们找不到任何太阳黑子，这是测量波前的参考，因为它接近太阳极小期，但我们最终确定了自适应光学系统的每个组件都工作良好。我们在一些科学会议上介绍了我们的自适应光学系统的发展。为了进一步发展自适应光学系统，我们正在讨论与京都大学和北上工业大学的合作。少

To investigate the various active phenomena occurring in the solar atmosphere is scientifically very important because they are the basic phenomena in the stellar atmosphere and also they show the plasma phenomena which cannot be reproduced in a laboratory, and furthermore, they affect the plasma environment of the earth much. To study such active phenomena, it is essentially important to observe the surface structure of the sun with a high spatial resolution. The adaptive optics is the key technology to get high resolution in the ground-base observation. We have been developing an adaptive optics system for the solar observation to realize the observation at the diffraction limit resolution with a 1-m class telescope in near future.We firstly designed the outline of the adaptive optics system, and introduced a deformable mirror which is the key device for the wavefront control. The control parameters for the deformable mirror were obtained from an experiment to establish the relation … More between the applied control signal to the mirror and the corresponding wavefront change measured with an interferrometer. Since the actual calculation of the wavefront and the control of the mirror require a high-speed (several hundred cycles per second), we developed a high-speed real-time software. Finally we completed the integration of the system.We attached our system to the Domeless Solar Telescope of the Hida Observatory, Kyoto, which is a 60-cm solar telescope, to test the system with the real solar images. Unfortunately, sometimes we could not find any sunspot, which is the reference to measure the wavefront, because it was near the solar minimum, but we finally confirmed that each component of the adaptive optics system is working well.We gave presentations in some scientific meetings on our development of the adaptive optics system.For further development of the adaptive optics system, we are discussing on the collaboration with the Kyoto University and the Kitami Institute of Technology. Less