NSWP: Synoptic Solar Magnetic Field Measurements at the Mt. Wilson 150-foot Tower Telescope in Support of Heliospheric Predictions and Modeling

太阳表面磁场是日球层磁场结构的锚点。这项提议的努力将通过继续和加强威尔逊山上150英尺高的太阳塔的天气观测计划，提高PI预测近地日球层环境状态的能力。在每个晴朗的日子里，威尔逊山天文台（MWO）项目提供了多达20张完整的圆盘磁图，它对光球场的每日测量结果被NOAA（国家海洋和大气管理局）的空间环境中心用于预测近地日球层的状态。MWO提供了良好的空间分辨率、校准良好的磁场零点和可追溯到1967年的时间覆盖的独特组合。这项建议将使这一项目得以继续，并通过用户发起的基于网络的检索过程向社区分发新的数据产品。本研究拟研究常用的势理论模型，作为表示太阳与太阳风之间磁场的方法，并研究用视距磁图估计电流的可能性。他将观测到的横向场与从势场理论推导出的场进行了比较，发现了实质性的分歧，他计划使用自己开发的一种方法来测量场的横向分量。他发现，如果在钠D线核心附近使用不同的谱线对进行基本磁场测量，就可以减少势场理论的问题。这对光谱线是在色球的底部而不是光球的中间形成的。PI将调查定期使用这种新线路对作为MWO常规数据产品的补充的优势。结合两个或多个频谱采样对进行基本磁场测量，可以估计场强的垂直梯度。通过利用他对不同高度的横向磁场分量的估计，PI将估计出南北方向磁场旋度的分量。这反过来将提供光球电流的估计，光球电流已被发现是日冕不稳定性的预测因子。PI将调查增强磁旋度的位置，以了解导致这些电流的磁结构。

The solar surface magnetic field is the anchor point for the structure of the heliospheric magnetic field. This proposed effort will improve the PI's ability to predict the state of the near-earth heliospheric environment through a continuation and enhancement of the synoptic program of observations at the 150-foot solar tower on Mt. Wilson. Each clear day, the Mt. Wilson Observatory (MWO) program contributes up to twenty full disk magnetograms, and its daily measurements of the photospheric field are used operationally by the Space Environment Center of NOAA (National Oceanic and Atmospheric Administration) to predict the state of the near-earth heliosphere. The MWO provides a unique combination of good spatial resolution with a well-calibrated magnetic field zero point and a temporal coverage extending back to 1967. This proposal will enable the continuation of this project and the distribution of new data products to the community through a user-initiated, web-based retrieval process.The proposer plans to investigate the commonly used potential theory model as the method of representing the magnetic field between the Sun and solar wind, and to investigate the possibility of estimating electric currents from line-of-sight magnetograms. He plans to use a method he developed for measuring the field's transverse component, after he compared observed transverse fields with fields derived from the potential field theory and found substantial disagreements. He discovered that if a different spectral line pair near the core of the sodium D line is used to make the basic magnetic field measurement, the problems with the potential field theory are reduced. This spectral line pair is formed at the base of the chromosphere instead of in the middle of the photosphere. The PI will investigate the advantages of using this new line pair on a regular basis as an augmentation of MWO's regular data products. The combination of two or more spectral sampling pairs for the basic magnetic field measurement permits an estimation of vertical gradients in the field strength. By using his estimation of the transverse field components at different altitudes, the PI will estimate the component of the curl of the magnetic field in the north-south direction. This in turn will provide an estimate of photospheric electric currents, which have been found to be a predictor of coronal instability. The PI will investigate the locations of enhanced magnetic curl to learn about the magnetic configurations that lead to these currents.