Auroral pulsations and accompanying VLF emissions
Auroral pulsations and accompanying VLF emissions
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极光脉动和伴随的甚低频发射
DOI：
10.1007/s00585-999-0066-9
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发表时间：
1999
影响因子：
1.9
通讯作者：
K. Kaila
中科院分区：
文献类型：
--
作者：
V. Tagirov;V. Ismagilov;E. Titova;V. A. Arinin;A. Perlikov;J. Manninen;T. Turunen;K. Kaila
介绍了1991年2月15日在索丹屈莱（芬兰）进行的脉动极光斑和早晨极低频-甚低频发射的同步电视观测结果。极光脉动活动具有典型的脉动斑，其特征周期约为7秒。在1.0- 2.5kHz频率范围内，以0.3- 0.4s为间隔的窄频带嘶嘶声发射和合唱成分同时构成了ELF-VLF的主要活动。时间分辨率为0.04秒的极光图像的分析允许完全分开的极光光度的空间和时间变化的分析。发光极光补丁的行为和外观的ELF噪声型嘶嘶声发射和VLF合唱列车之间的相互对应被发现在两个间隔选择进行分析。虽然嘶嘶声发射与接近天顶的有限区域内的光度外观有关，但结构化的VLF发射伴随着该区域内的光度快速运动。脉动区的空间尺度约为45-50公里，光度在脉动区内以10-12公里的速度传播。本文根据流动回旋脉塞理论和电离层弛豫特性，讨论了一种解释5-15 s极光脉动的新方法。
Results of simultaneous TV observations of pulsating auroral patches and ELF-VLF-emissions in the morning sector carried out in Sodankylä (Finland) on February 15, 1991 are presented. Auroral pulsating activity was typical having pulsating patches with characteristic periods of about 7 s. Narrow-band hiss emissions and chorus elements at intervals of 0.3–0.4 s formed the main ELF-VLF activity in the frequency range 1.0–2.5 kHz at the same time. The analysis of auroral images with time resolution of 0.04 s allowed perfectly separate analysis of spatial and temporal variations in the auroral luminosity. Mutual correspondence between the behaviour of the luminous auroral patches and the appearance of ELF noise type hiss emissions and VLF chorus trains was found in two intervals chosen for analysis. While the hiss emissions were associated with the appearance of luminosity inside a limited area close to the zenith, the structured VLF emissions were accompanied by rapid motion of luminosity inside the area. The spatial dimension of the pulsating area was about 45–50 km and luminosity propagated inside it with velocity of about 10–12 kms. We discuss a new approach to explain the 5–15 s auroral pulsation based on the theory of flowing cyclotron maser and relaxation characteristics of ionosphere.