标题： 经向流在太阳/恒星磁场和磁周期生成中的作用 显示英文标题

标题： The role of meridional flow in the generation of solar/stellar magnetic fields and cycles

摘要： 经向环流对于通过将磁场从衰减的双极磁区（BMR）向极地方向输运从而生成太阳偶极磁场至关重要。 由于经向环流随着恒星自转率的变化而变化，预计这种环流会对恒星磁场活动周期的特性产生影响。 在这项研究中，我们利用STABLE模型（表面通量传输和 Babcock-Leighton发电机模型）探索了经向环流在太阳及类似恒星磁场生成中的作用。 我们发现适度的经向环流通过有效地将尾随极性通量驱赶到极地来增强极区磁场，而强烈的环流则倾向于将BMR的两种极性都向极地方向输运，这可能会削弱极区磁场。 我们的发现与表面通量输运模型所预期的结果完全一致。 同样，带状磁场最初随着适度的环流速度增加，然后在达到某个值后开始减少。 这一趋势是由于剪切效应和扩散效应的竞争作用所致。 此外，本研究强调了经向环流对恒星活动周期强度和持续时间的影响。 通过在STABLE模型中加入平均场流体力学模型的经向环流，我们展示了磁场强度最初随着恒星自转率增加，但在快速旋转的恒星中会下降，这为解释观测到的恒星磁场随自转率的变化提供了依据。 显示英文摘要

摘要： Meridional flow is crucial in generating the solar poloidal magnetic field by facilitating the poleward transport of the field from the decayed Bipolar Magnetic Regions (BMRs). As the meridional circulation changes with the stellar rotation rate, the properties of stellar magnetic cycles are expected to be influenced by this flow. In this study, we explore the role of meridional flow in generating magnetic fields in Sun and sun-like stars using STABLE, Surface flux Transport And Babcock-Leighton, dynamo model. We find that a moderate meridional flow increases the polar field by efficiently driving the trailing polarity flux toward the pole, while a strong flow tends to transport both polarities of BMRs poleward, potentially reducing the polar field. Our findings are in perfect agreement with what one can expect from the surface flux transport model. Similarly, the toroidal field initially increases with moderate flow speeds and then decreases after a certain value. This trend is due to the competitive effects of shearing and diffusion. Furthermore, our study highlights the impact of meridional flow on the cycle strength and duration in stellar cycles. By including the meridional flow from a mean-field hydrodynamics model in STABLE, we show that the magnetic field strength initially increases with the stellar rotation rate and then declines in rapidly rotating stars, offering an explanation of the observed variation of stellar magnetic field with rotation rate.