Model Development and Theory/Data Closure for the Photoelectron-Driven Polar Wind

本提案将进一步发展流体/动力学混合模型，并利用该模型研究极地风。在该模型中，极地风的热电子特征通过流体计算来描述，而超热电子特征以及H+和O+离子使用全局环境中的动力学模型来描述。考虑了种间的Columbo碰撞，计算了双极电场的自一致性。这种方法是第一个能够将光电子的全局碰撞物理纳入自洽描述的方法。在探索性计算中产生了从亚音速碰撞状态到超音速无碰撞状态连续变化的全局稳态极风解。这里的研究将首先致力于参数研究，以便更好地理解各种电离层边界条件及其对极地风外流的影响之间的复杂相互关系。模式调查的结果将与DE和Akebono卫星上的极地风实验数据得到的结果进行比较。

This proposal will further develop a hybrid fluid/kinetic model and use the model to investigate the polar wind. In this model, thermal electron features of the polar wind are described by fluid calculations while the suprathermal electron features, as well as H+ and O+ ions are described using a kinetic model in a global environment. Columbo collisions among species are taken into account and the ambipolar electric field is computed self consistently. This approach is the first to be able to incorporate the global collisional physics of photoelectrons into a self- consistent description. Global steady-state polar wind solutions that vary continuously from a subsonic collisional regime to a supersonic collisionless regime have been generated in exploratory calculations. The investigation here will be first devoted to parametric studies in order to better understand the complex inter- relations between various ionospheric boundary conditions and their effects on polar wind outflow. Results of the model investigations will be compared with results being obtained from polar wind data obtained from experiments on the DE and Akebono satellites.