论文标题
Sigmoid太阳冠状环中的站立扭结波：对冠状动脉学的影响
Standing kink waves in sigmoid solar coronal loops: implications for coronal seismology
论文作者
论文摘要
使用完整的三维磁性水力学数值模拟，我们研究了磁场sigmoidity或螺旋性对太阳冠状环的基本扭结振荡性能的影响。我们的模型由单个密度的冠状环组成，该环嵌入具有恒定α参数的无偶极力磁场中的等离子体中。对于没有sigmoidity的循环，我们发现基本纠结模式的数值确定的振荡周期与使用WKB理论计算的理论时期相匹配。相比之下，随着循环的乙状结肠性的增加，实际周期越来越小于WKB理论估计的时期。通过冠状地震学翻译，增加乙状结肠导致磁场估计值越来越多地向更高的值转移，甚至超过了所考虑的最高alpha值的平均值。然而，冠状磁场值的估计范围位于模拟/最大限制内，证明了稳健性的冠状动脉学。我们建议，如果可以通过其他方法可靠地估计，则可以利用地震磁场的绝对值估计中的差异来确定冠状环的自由能。
Using full three-dimensional magnetohydrodynamic numerical simulations, we study the effects of magnetic field sigmoidity or helicity on the properties of the fundamental kink oscillation of solar coronal loops. Our model consists of a single denser coronal loop, embedded in a plasma with dipolar force-free magnetic field with a constant alpha-parameter. For the loop with no sigmoidity, we find that the numerically determined oscillation period of the fundamental kink mode matches the theoretical period calculated using WKB theory. In contrast, with increasing sigmoidity of the loop, the actual period is increasingly smaller than the one estimated by WKB theory. Translated through coronal seismology, increasing sigmoidity results in magnetic field estimates which are increasingly shifting towards higher values, and even surpassing the average value for the highest alpha value considered. Nevertheless, the estimated range of the coronal magnetic field value lies within the mimimal/maximal limits, proving the robustness coronal seismology. We propose that the discrepancy in the estimations of the absolute value of the force-free magnetic field could be exploited seismologically to determine the free energy of coronal loops, if averages of the internal magnetic field and density can be reliably estimated by other methods.
