论文标题
关于对流和下面的偶极子磁场之间的动态相互作用 - I.非dynamo状态
On the dynamical interaction between overshooting convection and an underlying dipole magnetic field -- I. The non-dynamo regime
论文作者
论文摘要
由许多恒星深层内部的动力学动机,我们研究了对流过度的对流与辐射区域中的大规模多型球场之间的相互作用。我们已经在球形外壳中运行了一个3D Boussinesq数值计算的套件,该壳由对流区组成,其基础稳定区域最初包含偶极场。通过改变对流驾驶的强度,我们发现,在湍流较小的方向上,对流的作用是湍流扩散,比仅仅是分子扩散的速度更快地去除场。但是,在更湍流的制度中,湍流泵送变得更加有效,部分抵消了湍流扩散,从而导致田间在过冲的区域下方的局部积累。这些模拟表明,偶极场可能通过恒星参数的高度湍流对流运动局限于稳定区域。限制在平均意义上是大规模领域的,我们表明它是由均值场所思想合理地建模的。对于某些太阳模型,我们的发现特别有趣,太阳的某些模型需要限制在太阳辐射区域中,以便同时解释后者的均匀旋转和太阳tachocline的薄度。
Motivated by the dynamics in the deep interiors of many stars, we study the interaction between overshooting convection and the large-scale poloidal fields residing in radiative zones. We have run a suite of 3D Boussinesq numerical calculations in a spherical shell that consists of a convection zone with an underlying stable region that initially compactly contains a dipole field. By varying the strength of the convective driving, we find that, in the less turbulent regime, convection acts as turbulent diffusion that removes the field faster than solely molecular diffusion would do. However, in the more turbulent regime, turbulent pumping becomes more efficient and partially counteracts turbulent diffusion, leading to a local accumulation of the field below the overshoot region. These simulations suggest that dipole fields might be confined in underlying stable regions by highly turbulent convective motions at stellar parameters. The confinement is of large-scale field in an average sense and we show that it is reasonably modeled by mean-field ideas. Our findings are particularly interesting for certain models of the Sun, which require a large-scale, poloidal magnetic field to be confined in the solar radiative zone in order to explain simultaneously the uniform rotation of the latter and the thinness of the solar tachocline.