Nonlinear and Synergistic Effects of ULF Pc5, VLF Chorus, and EMIC Waves on Relativistic Electron Flux at Geosynchronous Orbit
Nonlinear and Synergistic Effects of ULF Pc5, VLF Chorus, and EMIC Waves on Relativistic Electron Flux at Geosynchronous Orbit
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DOI：
10.1029/2017ja025003
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发表时间：
2018-06
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影响因子：
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通讯作者：
L. Simms;M. Engebretson;M. Clilverd;C. Rodger;G. Reeves
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作者：
L. Simms;M. Engebretson;M. Clilverd;C. Rodger;G. Reeves
利用2005-2009年的观测数据，研究了地球同步轨道上测得的log 10相对论电子通量对超低频（ULF）Pc 5、甚低频（VLF）低频段合唱和电磁离子回旋（EMIC）波的线性和非线性响应.我们使用回归模型，将二次项和协同作用项。相对论电子通量对超低频Pc 5和甚低频合唱波的响应有线性和非线性两种。超低频Pc 5波有助于电子增强（在中等波活动）和损失（在高水平的波活动）。VLF合唱的非线性效应是积极的（即，导致加速度），增加了正线性效应。高水平的VLF合唱和ULF Pc 5波的中档值之间的协同作用效应导致更多的电子加速比将由一个简单的添加剂模型预测。同样，EMIC波（损失）的负面影响比与VLF合唱或ULF Pc 5波结合时的线性模型预测的影响更大。在扰动条件下（高KP），地球静止电子通量更强烈地响应相同水平的超低频Pc 5和甚低频合唱波。该通量也响应更多的超低频Pc 5和合唱波在向南BZ条件。非标准化回归系数模型，将非线性和协同效应的波浪，用于在未来的建模。
Using data covering the years 2005–2009, we study the linear and nonlinear responses of log10 relativistic electron flux measured at geosynchronous orbit to ultralow frequency (ULF) Pc5, very low frequency (VLF) lower band chorus, and electromagnetic ion cyclotron (EMIC) waves. We use regression models incorporating a quadratic term and a synergistic interaction term. Relativistic electron fluxes respond to ULF Pc5 and VLF chorus waves both linearly and nonlinearly. ULF Pc5 waves contribute both to electron enhancement (at midrange wave activity) and loss (at high levels of wave activity). Nonlinear effects of VLF chorus are positive (i.e., cause acceleration), adding to the positive linear effects. Synergistic interaction effects between high levels of VLF chorus and midrange values of ULF Pc5 waves result in more electron acceleration than would be predicted by a simpler additive model. Similarly, the negative effect of EMIC waves (losses) is more influential than would be predicted by a linear model when combined with either VLF chorus or ULF Pc5 waves. During disturbed conditions (high Kp), geostationary electron flux responds more strongly to the same levels of ULF Pc5 and VLF chorus waves. This flux also responds more to ULF Pc5 and chorus waves during southward Bz conditions. Unstandardized regression coefficients for models incorporating nonlinear and synergistic effects of waves are presented for use in future modeling.