Substorm injection and solar wind dynamic pressure have long been considered as two main drivers of electromagnetic ion cyclotron (EMIC) wave excitation, but clear observational evidence is still lacking. With Van Allen Probes data from 2012–2017, we have investigated the roles of the two EMIC wave drivers separately, by using time‐modified AE⁺ and . Both the occurrence rate and magnetic amplitude of waves significantly increase with the enhancement of each index. During large AE⁺, EMIC waves are mainly generated in the dusk sector (16 ≤ MLT ≤ 20) and near the magnetic equator (|MLAT| < 10°). This is presumably due to substorm‐injected protons drifting from midnight sector to the plasmaspheric bulge. While during large , EMIC waves mainly occur in the noon sector (9 ≤ MLT ≤ 15). But there exist higher‐latitude (10° < |MLAT| < 20°) source regions besides equatorial source, possibly due to the minimum B regions. Our results provide strong observational support to existing generation mechanisms of EMIC waves in the Earth's magnetosphere.

中文翻译：

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亚暴注入和地球磁层中太阳风压增强引起的EMIC波激发的统计证据：两种不同的EMIC波源

长期以来，亚暴雨注入和太阳风动压一直被认为是电磁离子回旋加速器（EMIC）波激发的两个主要驱动力，但是仍然缺乏清晰的观测证据。借助Van Allen Probes 2012-2017年的数据，我们使用时间修改后的AE ⁺和分别研究了两个EMIC波驱动器的作用。随着每个指标的增加，波的发生率和磁振幅都显着增加。在较大的AE ⁺期间，EMIC波主要在黄昏区（16≤MLT≤20）和磁赤道附近（| MLAT | <10°）产生。据推测，这是由于注入亚暴的质子从午夜扇形漂移到等离子层凸起。在大期间，EMIC波主要发生在正午扇区（9≤MLT≤15）。但是，除了赤道源以外，还有更高纬度的源区（10°<| MLAT | <20°），可能是由于B区域最小。我们的结果为地球磁层中EMIC波的现有生成机制提供了有力的观测支持。