Magnetic Reconnection in the Solar Corona

Montana State University, Bozeman MT

Investigators

Abstract

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.