Study of geospace storms based on a new observation-based model of the inner magnetosphere

提出了一种新的磁层内环电流粒子自洽动力学模型。导出了一组包含粒子动力学和电磁场自洽发展的非线性时间演化方程。粒子输运用一个五维无碰撞漂移动力学方程来描述，其中粒子的运动轨迹由它们的导向中心在时变电磁场的影响下近似表示。电磁场的时间演化遵循麦克斯韦方程，粒子通过电流反馈。开发了一个三维空间（或五维相空间）求解全球内磁层方程组的数值模拟程序。结果表明，所建立的模型可以很好地描述低频等离子体波的传播。研究还发现，自洽耦合会影响高能粒子特别是低能粒子的输运以及场向电流的强度和空间分布。这些初步结果表明自洽耦合在全球地磁风暴发展中的重要性。我们的方法扩展了模拟内磁层发生的风暴时间现象的能力。这些包括突然开始（SCs）、亚暴、超高频波和其他相关现象。

A new self-consistent and kinetic model for ring current particles in the inner magnetosphere is presented. A closed set of nonlinear time evolution equations is derived that incorporates kinetic particle dynamics and self-consistent development of the electromagnetic field. The particle transport is described by a five-dimensional collisionless drift kinetic equation, in which particle trajectories are approximated by their guiding centers under the influence of a time-dependent electromagnetic field. The time evolution of the electromagnetic field follows the Maxwell equations with the feedback from particles through electric currents. A numerical simulation code solving the system of equations in a global inner magnetosphere in three spatial dimensions(or five dimensions in phase space) is developed. It is demonstrated that the propagation of low-frequency plasma waves can successfully be described by the developed model. It is also found that the self-consistent coupling could affect the transport of energetic particles especially at low energies as well as the intensity and spatial distribution of field-aligned currents. These preliminary results suggest the importance of the self-consistent coupling in the global development of geomagnetic storms. Our approach extends the capability of modeling storm time phenomena occurring in the inner magnetosphere. These include sudden commencements(SCs), substorms, and ULF waves, and other associated phenomena.