Abstract. The ICE (Instrument Champ Electrique) experiment on board the DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite recorded frequency-banded wave emissions below the electron cyclotron frequency, with band spacing ≳ frequency low-hybrid resonance, in the vicinity of the magnetic equatorial plane. Those radiations were observed in the beginning of the year 2010 on the night side of Earth and rarely on the day side. We distinguish two components: one appears as frequency bands continuous in time between a few kilohertz and up to 50 kHz, and the other one is from 50 to 800 kHz. The first component exhibits positive and negative frequency drift rates in the Southern Hemisphere and Northern Hemisphere, at latitudes between 40 and 20 ∘ . The second one displays multiple spaced frequency bands. Such bands mainly occur near the magnetic equatorial plane with a particular enhancement of the power level when the satellite latitude is close to the magnetic equatorial plane. We show in this study the similarities and the discrepancies between the non-free-space DEMETER frequency-banded emissions and the well-known free-space terrestrial kilometric radiation. The hollow cones of the DEMETER frequency-banded wave emissions are oriented towards Earth's ionosphere. We suggest that the source region is localized in regions poleward of the plasmapause where the ratio of the plasma frequency to gyro-frequency is smaller than one.

中文翻译：

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在电子回旋频率以下观测到的低空频带赤道辐射

摘要。DEMETER（地震区发射的电磁辐射检测）卫星上的 ICE（Instrument Champ Electrique）实验记录了电子回旋频率以下的频带波发射，频带间距 ≳ 频率低混合共振，在附近磁赤道平面。这些辐射是在 2010 年初在地球的夜晚一侧观测到的，而在白天一侧则很少观测到。我们区分两种成分：一种表现为在几千赫兹到 50 kHz 之间在时间上连续的频带，另一种表现为从 50 到 800 kHz。第一个分量在南半球和北半球的 40 到 20 ∘ 之间的纬度上表现出正和负频率漂移率。第二个显示多个间隔的频带。当卫星纬度接近磁赤道平面时，这些频带主要出现在磁赤道平面附近，并且功率水平特别增强。我们在这项研究中展示了非自由空间 DEMETER 频带发射与众所周知的自由空间陆地千米辐射之间的相似之处和差异。DEMETER 频带波发射的空心锥面向地球的电离层。我们建议源区位于等离子体层顶的两极区域，其中等离子体频率与陀螺频率的比率小于 1。我们在这项研究中展示了非自由空间 DEMETER 频带发射与众所周知的自由空间陆地千米辐射之间的相似之处和差异。DEMETER 频带波发射的空心锥面向地球的电离层。我们建议源区位于等离子体层顶的两极区域，其中等离子体频率与陀螺频率的比率小于 1。我们在这项研究中展示了非自由空间 DEMETER 频带发射与众所周知的自由空间陆地千米辐射之间的相似之处和差异。DEMETER 频带波发射的空心锥面向地球的电离层。我们建议源区位于等离子体层顶的两极区域，其中等离子体频率与陀螺频率的比率小于 1。