Development of Infrared Instrumentation for High-Resolution and High-Precision Solar Magnetic Field Observations

太阳光谱中1至2.2微米的近红外部分是研究太阳磁场的最佳诊断工具之一。在这些波长下，存在一组光谱线，可以精确测量太阳大气层中从光球层到色球层再到日冕的三维空间的磁场。这一研究项目将把这种观测与目前在两个地点建立的高分辨率和高动态范围望远镜能力结合起来：萨克拉门托峰国家太阳观测台和夏威夷大学天文学研究所的米斯太阳观测台。其目的是生产一套仪器，用于对太阳磁场进行精确的三维遥感。小尺度磁特征的研究需要在小视场（FOV）上进行高空间和时间分辨率的观测。日冕磁场的测量需要高灵敏度的光谱偏振在一个大的FOV，这只能实现降低空间和时间分辨率，鉴于现有的日冕照相能力。为满足这些广泛的观测要求，本项目将研制两种仪器：一种用于国家统计局邓恩太阳望远镜的设施红外分光偏振仪。它将与DST的新的高阶自适应光学系统一起运行，从而能够在大视场范围内以高空间分辨率和中等时间分辨率观测小尺度光球磁场以及太阳黑子和活动区磁场。基于分布式大幅面光纤积分场单元（IFU）的红外成像偏振光谱仪（IRIS）。IFU成像光谱测量扩展二维场的光谱，无需扫描。与AO系统相结合，它可以在观测太阳光球时在相当大的FOV上实现最高的空间和时间分辨率。在MSO的SOLAR-C日冕仪上，IFU成像光谱学将以中等的空间和时间分辨率有效地绘制大规模日冕磁场。

The near-infrared part of the solar spectrum between 1 and 2.2 microns is one of the best diagnostic tools for studying solar magnetic fields. At these wavelengths, sets of spectral lines exist that enable precise measurements of the magnetic fields across a large three-dimensional volume of the solar atmosphere, from the photosphere, through the chromosphere, and into the solar corona. This research project would integrate such observations with the high-resolution and high-dynamic-range telescopic capabilities now established at two sites: the National Solar Observatory at Sacramento Peak (NSO/SP) and the Mees Solar Observatory (MSO) of the Institute for Astronomy (IfA) at the University of Hawaii. The aim would be to produce a suite of instruments for precise three-dimensional remote sensing of solar magnetic fields. Study of small-scale magnetic features requires high spatial and time resolution observations over a small field of view (FOV). Measurement of coronal magnetic fields demands high-sensitivity spectropolarimetry over a large FOV, which can be achieved only with reduced spatial and time resolution, given existing coronagraphic capabilities. Two instruments would be developed in this project to meet these broad observational requirements: A Facility IR Spectropolarimeter (FIRS) for the Dunn Solar Telescope (DST) of NSO/SP. This would be a conventional long-slit spectrograph with an innovative multiple-slit design to enhance its efficiency. It would be operated in conjunction with the new high-order adaptive optics (AO) system of the DST, allowing observations of small-scale photospheric magnetic fields, as well as sunspot and active region magnetic fields, over a large FOV with high spatial and moderate time resolution. An IR Imaging Spectropolarimeter (IRIS) based on distributed large-format fiber optics integral field units (IFU). IFU imaging spectroscopy measures the spectra of extended two-dimensional fields without scanning. Combined with an AO system, it can achieve the highest spatial and time resolution possible over a substantial FOV when observing the solar photosphere. On the SOLAR-C coronagraph at MSO, IFU imaging spectroscopy would efficiently map the large-scale coronal magnetic fields with moderate spatial and time resolution.