标题： 极区磁场和太阳活动周的变化源于双极磁区的非规则特性 显示英文标题

标题： Variabilities in the polar field and solar cycle due to irregular properties of Bipolar Magnetic Regions

摘要： 太阳表面倾斜的双极磁区（BMR）的衰减和弥散被观测到会产生大规模的环向磁场，这作为下一个太阳黑子周期的种子场起着重要作用。然而，BMR的各种性质，即倾角、相邻浮现的时间延迟、位置和磁通量，都表现出不规则的变化。 先前的研究表明，这些变化会导致极区磁场的变化。 在这项研究中，我们首先证明了我们的三维运动学发电机模型STABLE再现了表面磁通量输运（SFT）模型的稳健特征，即由BMR位置的纬度引起的偶极矩生成的变化。 利用STABLE在SFT和发电机模式下，通过改变单个BMR属性并保持所有周期中的分布相同来进行模拟，这是受到观测启发的。 我们发现，由于时间延迟或BMR纬度分布中的随机性产生的影响，在极区磁场和太阳周期上几乎不会产生变化。然而，由于BMR磁通量分布的随机性会产生显著效果，而Joy定律周围的倾角散布则产生了最大的变化。 我们的对比分析表明，Joy定律周围的BMR倾角散布是太阳周期变化的主要原因。 此外，我们的模拟还显示，BMR浮现的时间延迟依赖于磁场会产生更真实的磁场周期特征，与观测结果一致。 显示英文摘要

摘要： Decay and dispersal of the tilted Bipolar Magnetic Regions (BMRs) on the solar surface are observed to produce large-scale poloidal field, which acts as the seed for the toroidal field and, thus, the next sunspot cycle. However, various properties of BMR, namely, the tilt, time delay between successive emergences, location, and flux, all have irregular variations. Previous studies show that these variations can lead to changes in the polar field. In this study, we first demonstrate that our 3D kinematic dynamo model, STABLE, reproduces the robust feature of the surface flux transport (SFT) model, namely the variation of the generated dipole moment with the latitude of the BMR position. Using STABLE in both SFT and dynamo modes, we perform simulations by varying the individual properties of BMR and keeping their distributions the same in all the cycles as inspired by the observations. We find that randomness due to the distribution in either the time delay or the BMR latitude produces negligible variation in the polar field and the solar cycle. However, randomness due to BMR flux distribution produces substantial effects, while the scatter in the tilt around Joy law produces the largest variation. Our comparative analyses suggest that the scatter of BMR tilt around Joy law is the major cause of variation in the solar cycle. Furthermore, our simulations also show that the magnetic field-dependent time delay of BMR emergence produces more realistic features of the magnetic cycle, consistent with observation.