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首页> 外文期刊>The Astrophysical journal >The Steady Global Corona and Solar Wind: A Three-dimensional MHD Simulation with Turbulence Transport and Heating
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The Steady Global Corona and Solar Wind: A Three-dimensional MHD Simulation with Turbulence Transport and Heating

机译:稳定的全球电晕和太阳风:湍流传输和加热的三维MHD模拟

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摘要

We present a fully three-dimensional magnetohydrodynamic model of the solar corona and solar wind with turbulence transport and heating. The model is based on Reynolds-averaged solar wind equations coupled with transport equations for turbulence energy, cross helicity, and correlation scale. The model includes separate energy equations for protons and electrons and accounts for the effects of electron heat conduction, radiative cooling, Coulomb collisions, Reynolds stresses, eddy viscosity, and turbulent heating of protons and electrons. The computational domain extends from the coronal base to 5?au and is divided into two regions: the inner (coronal) region, 1–30?R ☉, and the outer (solar wind) region, 30?R ☉–5?au. Numerical steady-state solutions in both regions are constructed by time relaxation in the frame of reference corotating with the Sun. Inner boundary conditions are specified using either a tilted-dipole approximation or synoptic solar magnetograms. The strength of solar dipole is adjusted, and a scaling factor for magnetograms is estimated by comparison with Ulysses observations. Except for electron temperature, the model shows reasonable agreement with Ulysses data during its first and third fast latitude transits. We also derive a formula for the loss of angular momentum caused by the outflowing plasma. The formula takes into account the effects of turbulence. The simulation results show that turbulence can notably affect the Sun's loss of angular momentum.
机译:我们提出了具有湍流传输和加热的太阳电晕和太阳风的完整三维磁流体动力学模型。该模型基于雷诺平均太阳风方程以及湍流能量,交叉螺旋和相关尺度的输运方程。该模型包括质子和电子的单独能量方程,并考虑了电子热传导,辐射冷却,库仑碰撞,雷诺应力,涡流粘度以及质子和电子的湍流加热的影响。计算域从冠底延伸到5?au,并分为两个区域:内部(日冕)区域1–30?R☉和外部(太阳风)区域30?R☉-5?au 。通过在与太阳共同旋转的参考系中的时间弛豫来构造两个区域中的数值稳态解。使用倾斜偶极近似法或天气太阳磁图来指定内部边界条件。调整了太阳偶极子的强度,并通过与尤利西斯(Ulysses)的观测结果进行比较,估算了磁图的比例因子。除了电子温度,该模型在第一次和第三次快速纬度转换过程中显示出与Ulysses数据的合理一致性。我们还导出了由流出的等离子体引起的角动量损失的公式。该公式考虑了湍流的影响。仿真结果表明,湍流可以显着影响太阳角动量的损失。

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