论文标题
太阳的卑鄙线场
The Sun's Mean Line-of-Sight Field
论文作者
论文摘要
我们将Sun-As-A-Star磁场（即平均场）视为光电场的球形谐波组件的滤波器，并计算该滤波器的透射系数。每个谐波的系数，$ y_ {l}^{m} $，根据它们对$ b_ {0} $的依赖，在三个表中列出，观察者在恒星的层坐标系统中的纬度。这些系数用于解释Wilcox太阳能天文台的每日平均场测量的46年序列。我们发现该字段的非轴对称部分起源于$ y_ {1}^{1} $，$ y_ {2}^{2} $，以及$ y_ {3}^{3}^{3} {3} $和$ y_ {3} $和$ y_ {3}^{1}^{1} $ harmonic Components的组合。该字段的轴对称部分以$ y_ {2}^{0} $加上$ b_ {0} $ - 依赖性组合的$ y_ {1}^{0} $和$ y_ {3}^{0} $组件的依赖组合。该场的功率谱的峰值在与〜27天的会议赤道旋转周期及其第二和第三谐波相对应的频率下。这些峰中的每个峰都在其低频侧都有精细的结构，表明磁性模式在差异旋转和子午流动的影响下缓慢旋转。基本模式的侧带分为对应于〜28.5和〜30天的峰，这些峰倾向于在最大黑子开始时发生，而〜27天的周期往往发生在最大太阳点的结束时。我们期望在其他类似太阳的恒星的磁性观察中发生类似的旋转边带，并成为对这些恒星中对流和磁场的小星言学研究的有用补充。
We regard the Sun-as-a-star magnetic field (i.e. the mean field) as a filter for the spherical harmonic components of the photospheric field, and calculate the transmission coefficients of this filter. The coefficients for each harmonic, $Y_{l}^{m}$, are listed in three tables according to their dependence on $B_{0}$, the observer's latitude in the star's polar coordinate system. These coefficients are used to interpret the 46-yr sequence of daily mean-field measurements at the Wilcox Solar Observatory. We find that the non-axisymmetric part of the field originates in the $Y_{1}^{1}$, $Y_{2}^{2}$, and a combination of the $Y_{3}^{3}$ and $Y_{3}^{1}$ harmonic components. The axisymmetric part of the field originates in $Y_{2}^{0}$ plus a $B_{0}$-dependent combination of the $Y_{1}^{0}$ and $Y_{3}^{0}$ components. The power spectrum of the field has peaks at frequencies corresponding to the ~27-day synodic equatorial rotation period and its second and third harmonics. Each of these peaks has fine structure on its low-frequency side, indicating magnetic patterns that rotate slowly under the influence of differential rotation and meridional flow. The sidebands of the fundamental mode resolve into peaks corresponding to periods of ~28.5 and ~30 days, which tend to occur at the start of sunspot maximum, whereas the ~27-day period tends to occur toward the end of sunspot maximum. We expect similar rotational sidebands to occur in magnetic observations of other Sun-like stars and to be a useful complement to asteroseismology studies of convection and magnetic fields in those stars.
