Modeling of Auroral Kilometric Radiation (AKR) Ordered Fine Structure via Electromagnetic and Electrostatic Ion Cyclotron (EMIC/EIC) Wave Stimulation and Particle Interaction

极光加速区的上升流区是电子和离子加速、波粒相互作用、磁层-电离层（M-I）耦合和波产生的极动态区域。在这个区域中，观察到许多不同类型的等离子体波，包括强烈的静电和电磁离子回旋（EIC/EMIC）波。它也是极光公里辐射（AKR）的来源区域，这是最强大的地面无线电发射。在这个区域中的向上电流被EIC和EMIC波干扰和调制，因此提供了M-I耦合动力学的重要组成部分。AKR的频率与时间谱图揭示了一个窄带精细结构，出现湍流，但显示频率漂移的特定功能。了解AKR精细结构的来源对于了解波产生机制的细节以及整体粒子/波能量平衡至关重要。最近已经鉴定了一类新的AKR精细结构，称为有序精细结构或条纹。新的数据表明，AKR有序精细结构是电磁离子回旋（EMIC）和静电离子回旋（EIC）波激发的结果。本计画将利用三维粒子模拟程序，研究极光区EMIC/EIC波的成长与AKR有序精细结构的激发。模拟确定所观察到的有序精细结构的形态如何取决于刺激AKR的波的频率和波长。这些模拟还将有助于空间和等离子体科学相关领域的发展。

The upward current region of the auroral acceleration region is an extremely dynamic region of electron and ion acceleration, wave-particle interaction, magnetospheric-ionospheric (M-I) coupling, and wave generation. In this region many different types of plasma waves are observed, including intense electrostatic and electromagnetic ion cyclotron (EIC/EMIC) waves. It is also the source region of auroral kilometric radiation (AKR), the most powerful terrestrial radio emission. Upward electric currents in this region are disrupted and modulated by EIC and EMIC waves, and thus provide a significant component of the M-I coupling dynamics. Frequency- vs. -time spectrograms of AKR reveal a narrow-banded fine structure that appears turbulent but displays specific features of frequency drift. Understanding the source of AKR fine structure is critical to understanding details of the wave generation mechanism, and the overall particle/wave energy balance. A new class of AKR fine structure referred to as ordered fine structure or striations has more recently been identified. The new data have suggests that AKR ordered fine structure results from stimulation by electromagnetic ion cyclotron (EMIC) and electrostatic ion cyclotron (EIC) waves. This project will use a 3-D particle-in-cell (PIC) plasma simulation code to study of the growth of EMIC/EIC waves in the auroral region and the stimulation of AKR ordered fine structure. The simulations determine how the morphology of the observed ordered fine structure depends on the frequency and wave length of the waves stimulating the AKR. The simulations will also contribute to developments in related fields of space and plasma science.