Theoretical Studies of Solar Flares and Active Regions

该理论研究将用于了解磁场和电流系统在太阳耀斑中的作用，以及了解耀斑和活动区色球层和日冕层等离子体流与辐射的相互作用。具体而言，本工作将进一步发展x型中性点磁重联的解析描述，并将研究扩展到数值模拟；根据矢量磁图，研究气体压力对光球磁场的影响；利用有源区磁场模型确定沿日冕环的横截面积变化，用于流体力学和粒子研究；改进了耀斑渐变阶段演化模型，将复杂的流体力学描述简化为一个简单的常微分方程，使整个耀斑的模拟成为可能；将类似的技术应用于有源回路的热稳定性研究；并开发一种新的，更简单的；用于脉冲色球耀斑研究的更快的辐射流体动力学代码。这些问题将用气体动力学、辐射传递和磁流体动力学方程的解析和数值技术来研究。这项工作将有助于解释MAX '91期间地面光学望远镜的光谱数据和矢量磁图。* * *

This theoretical research will be conducted to understand the role of magnetic fields and current systems in solar flares, and to understand the interaction of plasma flows with radiation in both the chromosphere and corona of flares and active regions. Specifically, this effort will further develop an analytic description of magnetic reconnection at an X-type neutral point, and extend the studies to numerical simulation; study the influence of gas pressure on photospheric magnetic fields as inferred from vector magnetograms; use active region magnetic field models to determine cross-sectional area variation along coronal loops for use in hydrodynamic and particle studies; improve a model for the evolution of the gradual phase of flares, which reduces the complex hydrodynamic description to a simple ordinary differential equation, making simulations of the entire flare feasible; apply similar techniques to studies of thermal stability of active region loops; and develop a new, simpler; faster, radiation-hydrodynamics code for studies of the impulsive chromospheric flare. These problems will be studied with analytic and numerical techniques applied to the gasdynamic, radiation transfer, and magnetohydrodynamic equations. This work will aid in interpreting spectroscopic data and vector magnetograms from ground based optical telescopes during MAX '91. ***