用三维正向建模检验日冕加热理论
Testing Theories of Solar Coronal Heating with Three-Dimensional Forward Modeling
浏览论文内容
中文总结 AI 辅助
研究太阳日冕加热理论，通过三维正向建模，利用磁场势场外推、一维模型填充等离子体参数并计算强度，结合多种加热参数化及间歇性加热冷却影响，找到与实测强度最佳匹配的参数范围，参数值与特定模型预测一致。
中文摘要 AI 辅助
经过近一个世纪的推测，太阳日冕加热的物理过程仍不明确。极紫外和X射线波段对日冕环的观测提供了诸多见解，如加热率随局部磁场强度单调增加的约束。然而，关于加热的详细理论解释仍有数十种相互竞争。本文通过从磁场的势场外推开始构建日冕的三维模拟，利用一维模型沿单个环填充等离子体密度和温度，然后计算光学薄强度以与太阳动力学天文台和日之出的数据进行比较。正向建模的一个新方面是使用包括波耗散、重联、纳米耀斑和湍流级联等多种过程的加热参数化。还包括沿未解析细丝的间歇性加热和冷却的影响。在允许日冕加热处方自由变化后，发现了一组狭窄的参数，能与一组超过500个在太阳极小和极大期独立测量的强度产生最佳一致性。这些参数值与不平衡磁流体动力学湍流模型预测的值一致，但不一定排除其他加热过程的贡献。
英文摘要
After almost a century of speculation, the physical processes responsible for heating the Sun's corona remain uncertain. Observations of coronal loops at extreme ultraviolet and X-ray wavelengths have provided substantial insights, such as the constraint that heating rates increase monotonically with local magnetic field strength. However, there remain dozens of competing suggestions for detailed theoretical explanations of the heating. There remains a need to compare the predictions of these theories with one another, and with real data, so the most likely mechanisms can be determined. In this paper, we build three-dimensional simulations of the corona by starting with potential-field extrapolations for the magnetic field, filling in plasma densities and temperatures along individual loops using one-dimensional models, then computing optically thin intensities for comparison with data from the Solar Dynamics Observatory and Hinode. One new aspect of this forward modeling is the use of parameterizations for heating that include a wide variety of processes such as wave dissipation, reconnection, nanoflares, and turbulent cascade. We also include the effects of intermittent heating and cooling along unresolved strands in the form of time-averaged multithermal broadening of the local differential emission measure. After allowing the coronal heating prescription to vary freely, we found a narrow range of parameters that produce optimal agreement with a set of more than 500 independently measured intensities at solar minimum and maximum. The values of these parameters are consistent with those predicted by models of imbalanced magnetohydrodynamic turbulence, but this does not necessarily exclude contributions from other heating processes.
