Magnetic Reconnection in the Solar Corona

日冕中的磁重联

• 批准号: 0097227
• 负责人: Dana Longcope
• 金额: $ 23.71万
• 依托单位: Montana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-12-01 至 2005-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0097227&HistoricalAwards=false
• 关键词: Magnetic; Reconnection; Solar; Corona

The investigator will examine three-dimensional magnetic reconnection in the solar corona. The main effort comprises three overlapping theoretical investigations. First, numerical magnetohydrodynamics simulations will test the fundamental assumptions of the Minimum Current Corona. These simulations will fix adjustable parameters of the original model and point to the need for modifications. Second, the existing Minimum Current Coronal model will be modified to include helicity and helicity transport resulting from reconnection. This modified model will permit more accurate representations of observed magnetic fields and will test the hypothesis that helicity transport rather than flux transfer is the most energetically important aspect of reconnection. Finally, the details of the coronal reconnection process may be responsible for many aspects of coronal morphology including the occurrence of narrow structures called coronal loops. This possibility will be explored through a third investigation, a kinematic model of reconnection at three-dimensional current sheets. The results of this investigation will shed light on the range of loop diameters theoretically expected and the amount of excess energy that may heat these loops after their reconnection. Magnetic reconnection is a fundamental process occurring in the solar corona and the Earth's magnetosphere. Early investigations of magnetic reconnection produced local models set in two-dimensional geometry. While useful for demonstrating the basic feasibility of the process these models have done little to provide quantitative energetics in complex three-dimensional settings. The Minimum Current Corona, whose development was supported by prior NSF funding, has provided recent strides toward a quantitative three-dimensional model. This model predicts that the evolution of complex magnetic field, such as the solar corona, will involve intermittent flux transfer events accompanied by energy release. Moreover, the model quantifies the relationship between the processes of flux transfer and energy release. This relationship sets the level of energetic activity in each portion of the solar corona or the coronae of other stars.

研究人员将研究日冕中的三维磁场重联。主要工作包括三个重叠的理论研究。首先，数值磁流体力学模拟将测试最小电流电晕的基本假设。这些模拟将固定原始模型的可调整参数，并指出需要修改的地方。第二，现有的最小流日冕模型将被修改，以包括螺旋度和螺旋度传输导致的重联。这种修改后的模型将允许更准确地表示所观察到的磁场，并将测试的假设，螺旋度运输，而不是通量转移是最积极的重联方面。最后，日冕重连过程的细节可能是日冕形态的许多方面的原因，包括称为日冕环的狭窄结构的出现。这种可能性将探讨通过第三次调查，在三维电流片重联的运动学模型。这项研究的结果将阐明理论上预期的环直径范围以及在重新连接后可能加热这些环的多余能量的量。磁场重联是发生在日冕和地球磁层中的一个基本过程。磁重联的早期研究产生了二维几何的局部模型。虽然这些模型对证明该过程的基本可行性很有用，但在复杂的三维环境中，它们几乎没有提供定量的能量学。最小电流电晕，其发展是由以前的NSF资金支持，提供了最近的进步，定量三维模型。该模型预测，复杂磁场的演化，如太阳日冕，将涉及间歇性的磁通传输事件伴随着能量释放。此外，该模型量化了通量传递和能量释放过程之间的关系。这种关系决定了太阳日冕或其他恒星日冕的每一部分的能量活动水平。