Investigating the conditions of ELF/VLF wave propagation from space to the ground.

我们在芬兰的Oulujarvi （OUJ）安装了一个VLF接收器，位于Kannuslehto （KAN）现有接收器以南450公里处。KAN在Lovozero （LOZ）接收器以西400公里处。我们研究了KAN和LOZ之间共轭事件的特征。对OUJ和KAN之间的共轭事件进行了为期1个月的研究，发现了33个一对一对应的案例（相同的波/源区域）。这些例子使我们估计了VLF波的纬度范围（450公里），并深入了解了VLF的发生（约30%的总观测显示一对一的对应）。通过极化分析，对其电离层出口点的演化进行了研究。我们还开始了对共轭事件和VLF爆发补丁的OUJ和KAN数据进行统计分析的长期计划。

We installed a VLF receiver in Oulujarvi, Finland (OUJ) located 450 km south of the existing receiver at Kannuslehto (KAN). KAN is 400 km west of the receiver at Lovozero (LOZ). We investigated characteristics of conjugated events between KAN and LOZ. A 1-month study of conjugated events between OUJ and KAN found 33 cases of one-to-one correspondence (same waves/source region). These cases give us an estimation of the latitudinal extent of VLF waves (450 km) and insight into VLF occurrence (~30% of total observations show one-to-one correspondence). Through polarization analysis, the investigation of the evolution of their ionospheric exit point is underway. We have also started long term plans for statistical analysis of OUJ and KAN data for conjugated events and VLF bursty-patches.