论文标题
在内层中的开放磁通量测量至0.13AU
Measurement of the Open Magnetic Flux in the Inner Heliosphere down to 0.13AU
论文作者
论文摘要
（删节）目的：我们尝试使用Parker太阳能探针（PSP）数据来确定对地层磁通量（$φ_H$）的可靠估计，分析与真正的开放通量（$φ_{OPEN} $）相比，这是多么易于高估，并评估其对时间和空间的依赖性，并比较了它的依赖性，并比较了该模型，并比较了潜在的估计（field surgese surgesess）。方法：我们使用PSP，立体声A和风中的数据比较了不同的计算方法。通过使用测量的径向趋势产生合成数据来探测波动和大规模结构对估计值的影响。最佳估计是根据时间和空间的函数计算的，并将其与PFSS模型的估计值进行了比较。结果：HMF载体的径向变化和帕克螺旋角的变化导致平均值和模式的标准指标随半径演变而成，而半径与矢量波动的中心值无关。最好通过将矢量投射到背景Parker螺旋方向来减轻这一点。然而，我们发现接近1AU的通量中的较小增强。局部倒置线线的比例与距太阳的径向距离生长，这仍然是造成这种过量的物理原因，但在PSP的Perihelia中可以忽略不计。同样，在PSP的围层中，波动的影响通常大大降低。总体最佳估计是〜2.5 nt Au2。对纬度或经度的强烈依赖是显而易见的。 PFSS模型可预测较低的值从1.2到1.8 nt Au2。 Conclusions: The heliospheric flux is robustly estimated relative to a mean Parker spiral direction at PSP`s perihelia where the decay of fluctuations and weakening importance of local flux inversions means $Φ_H$ ~ $Φ_{open}$.尽管如此，估计值仍然太高，无法用PFSS模型来解释，这支持了冠状模型低估了开放磁通量的想法。
(Abridged) Aim: We attempt to determine robust estimates of the heliospheric magnetic flux ($Φ_H$) using Parker Solar Probe (PSP) data, analyze how susceptible this is to overestimation compared to the true open flux ($Φ_{open}$), assess its dependence on time and space, and compare it to simple estimates from Potential Field Source Surface (PFSS) models. Methods: We compare different methods of computation using data from PSP, STEREO A and Wind. The effects of fluctuations and large scale structure on the estimate are probed by using measured radial trends to produce synthetic data. Best estimates are computed as a function of time and space, and compared to estimates from PFSS models. Results: Radially-varying fluctuations of the HMF vector and variation of the Parker spiral angle cause the standard metrics of the mean and mode to evolve with radius independent of the central value about which the vector fluctuates. This is best mitigated by projecting the vector into the background Parker spiral direction. Nevertheless, we find a small enhancement in flux close to 1AU. The fraction of locally inverted field lines grows with radial distance from the Sun which remains a possible physical reason for this excess, but is negligible at PSP`s perihelia. Similarly, the impact of fluctuations in general is much reduced at PSP`s perihelia. The overall best estimate is ~2.5 nT AU2 . No strong dependence on latitude or longitude is apparent. The PFSS models predict lower values from 1.2 to 1.8 nT AU2. Conclusions: The heliospheric flux is robustly estimated relative to a mean Parker spiral direction at PSP`s perihelia where the decay of fluctuations and weakening importance of local flux inversions means $Φ_H$ ~ $Φ_{open}$. Despite this, the estimate remains too high to be explained by PFSS models, supporting the idea that coronal models underestimate the open magnetic flux.
