CONSISTENT SCALING LAWS IN ANELASTIC SPHERICAL SHELL DYNAMOS
CONSISTENT SCALING LAWS IN ANELASTIC SPHERICAL SHELL DYNAMOS
复制标题
滞弹球壳发电机中一致的尺度定律
DOI：
10.1088/0004-637x/774/1/6
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
L. D. V.
中科院分区：
文献类型：
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作者：
Gastine;Christensen;Duarte;L. D. V.
数值发电机模型总是采用与自然物体中预期值相差几个数量级的参数值。然而，这样的模型已经成功地在定性再现行星和恒星发电机的属性。这种定性的协议燃料的想法，数值模型和天体物理对象可以在相同的渐近制度的动态。这可以通过探索模型的缩放行为来测试。对于对流驱动的不可压缩球壳发电机与恒定的材料特性，标度律已建立以前的流速和磁场强度的可用功率。在这里，我们使用滞弹性近似分析了273个直接数值模拟，其中还涉及与半径相关的磁、热和粘性扩散率的情况。与Boussinesq模型相比，这些模型更好地代表了气体巨行星和低质量恒星的条件。我们的研究提供了强有力的支持的假设，即平均速度和平均磁场强度的规模作为一个功能的浮力产生的功率以同样的方式为广泛的条件。
Numerical dynamo models always employ parameter values that differ by orders of magnitude from the values expected in natural objects. However, such models have been successful in qualitatively reproducing properties of planetary and stellar dynamos. This qualitative agreement fuels the idea that both numerical models and astrophysical objects may operate in the same asymptotic regime of dynamics. This can be tested by exploring the scaling behavior of the models. For convection-driven incompressible spherical shell dynamos with constant material properties, scaling laws had been established previously that relate flow velocity and magnetic field strength to the available power. Here we analyze 273 direct numerical simulations using the anelastic approximation, involving also cases with radius-dependent magnetic, thermal, and viscous diffusivities. These better represent conditions in gas giant planets and low-mass stars compared to Boussinesq models. Our study provides strong support for the hypothesis that both mean velocity and mean magnetic field strength scale as a function of the power generated by buoyancy forces in the same way for a wide range of conditions.