论文标题
估计快速风的反向映射中的不确定性
Estimating uncertainties in the back-mapping of the fast solar wind
论文作者
论文摘要
太阳风反向映射是弹道映射和磁性映射的组合。通过检查可能影响派生后映射位置的不同模型成分，我们旨在提供对源位置的更精确估计，并衡量对映射过程的信心。这可用于改善遥感与原位测量的连接。对于弹道映射，我们创建了自定义速度轮廓。这些轮廓受到对靠近太阳的快速太阳风的观察来限制的，并用于检查映射不确定性。从太阳能表面到源表面的冠状磁场拓扑是用PFSS外推建模的。通过向输入磁力图添加噪声并进行蒙特卡洛模拟来检查外推磁场的灵敏度，其中，对于多个噪声实现，我们计算了太阳风的源位置。接下来，检查自由参数的效果，例如源表面的高度，并得出统计估计。由于不确定性的不同，我们使用高斯混合物聚类来对后映射点进行分组，并为太阳风的源位置提供了置信区。此外，我们计算了许多指标来评估后映射结果，并通过检查3个高速流事件来评估其统计学意义。最后，我们探索了靠近太阳的旋律对太阳风的源区域的影响。我们的结果表明，源表面的高度在快速太阳风的源区域中产生最大的不确定性，然后选择速度曲线和输入磁图中的噪声。此外，我们显示出在太阳表面上得出置信区域的能力，该置信区代表了原位测得的快速太阳风的潜在源区域。
Solar wind back-mapping is a combination of ballistic mapping and magnetic mapping. By examining the different model ingredients that can affect the derived back-mapped position, we aim to provide a more precise estimate of the source location and a measure of confidence in the mapping procedure. This can be used to improve the connection of remote sensing with in situ measurements. For the ballistic mapping we created custom velocity profiles. These profiles are constrained by observations of the fast solar wind close to the Sun and are used to examine the mapping uncertainty. The coronal magnetic field topology from the solar surface up to the source surface is modeled with a PFSS extrapolation. The sensitivity of the extrapolated field is examined by adding noise to the input magnetogram and performing a Monte Carlo simulation, where for multiple noise realizations we calculate the source position of the solar wind. Next, the effect of free parameters, like the height of the source surface, is examined and statistical estimates are derived. We used Gaussian Mixture clustering to group the back-mapped points, due to different sources of uncertainty, and provide a confidence area for the source location of the solar wind. Furthermore, we computed a number of metrics to evaluate the back-mapping results and assessed their statistical significance by examining 3 high speed stream events. Lastly, we explored the effect of corotation, close to the Sun, on the source region of the solar wind. Our results show that the height of the source surface produces the largest uncertainty in the source region of the fast solar wind, followed by the choice of the velocity profile and the noise in the input magnetogram. Additionally, we display the ability to derive a confidence area on the solar surface that represents the potential source region of the in-situ measured fast solar wind.
