Viscous Effects in Magnetic Reconnection and Energy Dissipation in the Solar Corona

首席研究员计划分析粘性应力和粘性能量耗散在日冕磁化等离子体中的作用，因为粘性会强烈影响日冕磁场的动力学和能量学。他的团队将采用分析论证和磁流体动力学（MHD）模拟相结合的方法，研究粘性耗散对日冕加热和耀斑能量释放的贡献。该团队将把粘度、可压缩性和通量堆积的影响纳入一个稳定的Sweet-Parker重联模型；将预测的刻度与观测到的耀斑功率输出和重连射流的速度进行比较；获得描述日冕磁零点附近场扰动粘性衰减的新瞬态解；并评估这些过程对日冕加热的贡献。首席研究员打算将他的粘阻解与基于Hall MHD方程的无碰撞磁重联模型的数值结果进行比较，以确定这种分析何时有效，以及何时需要更严格（但更复杂的动力学）处理。预期的结果将有助于解释来自SOHO、Yohkoh、TRACE和日野等航天器的现有数据。更广泛地说，这项研究将有助于发展基于物理的空间天气模型，从而给社会带来好处。这些活动将有助于研究与教育的结合，并促进教学、培训和学习。项目由一名博士后研究科学家作为合作者参与，申请人本人（作为研究助理教授）将与美国新罕布什尔大学（UNH）的本科生和研究生进行互动，并担任论文委员会成员，丰富新罕布什尔大学学生的课堂教育和研究经验。

The principal investigator plans to analyze the role of viscous stresses and viscous energy dissipation in the magnetized plasma of the solar corona, since viscosity can strongly influence the dynamics and energetics of the magnetic field in the corona. His team will study the contribution of viscous dissipation to coronal heating and flare energy release by employing a combination of analytical arguments and magnetohydrodynamic (MHD) simulations. The team will incorporate the effects of viscosity, compressibility, and flux pile-up into a steady Sweet-Parker reconnection model; compare the predicted scalings with the observed flare power output and the speeds of reconnection jets; obtain new transient solutions describing the viscous decay of field disturbances in the vicinity of magnetic nulls in the solar corona; and evaluate the contribution of these processes to coronal heating. The principal investigator intends to compare his visco-resistive solutions with numerical results of modeling collisionless magnetic reconnection, based on Hall MHD equations, in order to determine when this analysis is valid and when a more rigorous (but more complicated kinetic) treatment is necessary.The expected results will help in interpreting the available data from spacecraft such as SOHO, Yohkoh, TRACE, and Hinode. More generally, the research will contribute to the development of physics-based models for space weather, with concomitant benefits to society. The activities will contribute to the integration of research and education, as well as promote teaching, training, and learning. The project involves the participation of a postdoctoral research scientist as collaborator, and the proposer himself (as a research assistant professor) will interact with University of New Hampshire (UNH) undergraduate and graduate students, serve on thesis committees, and enrich the classroom education and research experience of UNH students.