Magnetic field emerges at the surface of the Sun as sunspots and active regions. This process generates a poloidal magnetic field from a rising toroidal flux tube; it is a crucial but poorly understood aspect of the solar dynamo. The emergence of magnetic field is also important because it is a key driver of solar activity. We show that measurements of horizontal flows at the solar surface around emerging active regions, in combination with numerical simulations of solar magnetoconvection, can constrain the subsurface rise speed of emerging magnetic flux. The observed flows imply that the rise speed of the magnetic field is no larger than 150 m/s at a depth of 20 Mm, that is, well below the prediction of the (standard) thin flux tube model but in the range expected for convective velocities at this depth. We conclude that convective flows control the dynamics of rising flux tubes in the upper layers of the Sun and cannot be neglected in models of flux emergence.
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机译：磁场作为黑子和活跃区域出现在太阳表面。这个过程从上升的环形通量管产生极向磁场。这是太阳发电机的关键但尚不为人所知的方面。磁场的出现也很重要，因为它是太阳活动的关键驱动力。我们表明，在新兴活动区域周围的太阳表面水平流的测量，结合太阳磁对流的数值模拟，可以约束新兴磁通量的地下上升速度。观测到的流量暗示在20 Mm深度处磁场的上升速度不大于150 m / s，即远低于（标准）薄通量管模型的预测，但在对流预期的范围内在这个深度的速度。我们得出结论，对流流动控制着太阳高层中上升的通量管的动力学，在通量出现模型中不能忽略对流。
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