Whistler mode waves observed in the Earth's inner magnetosphere at frequencies between about 0.5 and 4 kHz which exhibit a nearly periodic time modulation of the wave intensity are called quasiperiodic (QP) emissions. Conjugate measurements of QP events at several different locations can be used to estimate their spatial extent and spatiotemporal variability. Results obtained using conjugate QP measurements provided by the ground‐based station Kannuslehto (L ≈5.5) and the Van Allen Probes spacecraft (L shells between about 1.1 and 6.5) between September 2012 and November 2017 are presented. Altogether, 26 simultaneously detected events were analyzed. The event modulation periods and frequency‐time structures were generally the same at all observation points. Spatial separations of the spacecraft and the ground‐based station during conjugate observations are typically within about 40° in azimuth and from about 1 to 3 in L shell. RBSP consistently observes events at lower L shells than Kannuslehto, with the event occurrence primarily inside of the plasmasphere. Ratios of Poynting fluxes observed by the spacecraft and on the ground are used to evaluate event intensity variations related to the spacecraft position. It is found that the intensity decreases considerably both at low L shells and outside of the plasmasphere. Finally, an event containing a gap in its frequency‐time structure related to a sudden change of its properties is analyzed in detail.

中文翻译：

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Van Allen探测器航天器和地面站Kannuslehto对准周期发射的共轭观测

在地球内部磁层中以大约0.5到4 kHz的频率观察到的惠斯勒模式波，表现出近乎周期性的波强度时间调制，被称为准周期（QP）发射。QP事件在几个不同位置的共轭测量可用于估计其空间范围和时空变异性。使用由基于地面的站Kannuslehto（提供共轭QP测量获得的结果大号≈5.5）和范艾伦探测器宇宙飞船（大号展示了2012年9月至2017年11月之间的大约1.1至6.5之间的炮弹）总共分析了26个同时检测到的事件。在所有观测点，事件调制周期和频率-时间结构通常是相同的。共轭观测期间，航天器和地面站的空间间隔通常在方位角约40°以内，在L壳内约1至3 。RBSP始终观察到比Kannuslehto更低的L壳处的事件，该事件主要发生在等离子层内部。航天器在地面上观察到的珀因廷通量比用于评估与航天器位置有关的事件强度变化。发现在低强度下强度均显着降低。L壳和等离子层外部。最后，将详细分析一个事件，该事件在其频率-时间结构中包含一个与其特性突然变化相关的间隙。