EMISSIONS BY THE ISIS 2 SATELLITE IN THE 19-24 MLT SECTOR
EMISSIONS BY THE ISIS 2 SATELLITE IN THE 19-24 MLT SECTOR
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DOI：
10.1029/ja082i016p02210
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发表时间：
1977-06
期刊：
影响因子：
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通讯作者：
A. Lui;D. Venkatesan;C. Anger;S. Akasofu;W. Heikkila;J. Winningham;J. Burrows
中科院分区：
文献类型：
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作者：
A. Lui;D. Venkatesan;C. Anger;S. Akasofu;W. Heikkila;J. Winningham;J. Burrows
报告了利用Isis 2号卫星上的仪器对19-24 MLT扇区的极光发射和粒子降水进行的同时观测。扩散极光的光学强度被发现主要是由一个相对均匀的沉淀之间的约100 eV和10 keV的低能电子单调的能谱。离散极光嵌入在扩散极光的内部，但通常是在向极的部分，是由高度结构化和强烈的电子沉淀造成的。相应的电子能谱由一个单调的组成部分，类似于在漫射极光和峰值组件往往比麦克斯韦谱窄。与扩散极光相关联的降水的几个特点支持的扩散极光的光学图像的向地球终止的等离子体片在极光高度的识别。这表明离散极光的源粒子位于沿着地磁场线，但通常靠近等离子体片的向极边界。高能电子（E > 40 keV）的背景边界经常被观察到延伸到离散极光的位置，一些清晰可辨的煎饼型俯仰角各向异性的情况表明，一些离散极光是在封闭的场线上。质子沉淀在离散和扩散极光区，但不显着的总能量通量的贡献，除了附近的赤道边界的扩散极光，质子通量在某些情况下可以占主导地位。
Simultaneous observations of auroral emissions and particle precipitation in the 19–24 MLT sector by instruments on the Isis 2 satellite are reported. The optical intensity of the diffuse aurora is found to be produced mainly by a relatively uniform precipitation of low-energy electrons between about 100 eV and 10 keV with monotonic energy spectra. Discrete auroras are embedded within but usually in the poleward portion of the diffuse aurora and are caused by highly structured and intense electron precipitation. The corresponding electron energy spectrum consists of a monotonic component similar to that in the diffuse aurora and a peaked component often narrower than a Maxwellian spectrum. Several characteristics of the precipitation associated with the diffuse aurora support the identification of the diffuse aurora as the optical image of the earthward termination of the plasma sheet at the auroral altitudes. This suggests that the source particles of discrete auroras lie along the geomagnetic field lines within but usually near the poleward boundary of the plasma sheet. The background boundary for energetic electrons (E > 40 keV) is frequently observed to extend up to the location of discrete auroras, some cases of clearly discernible pancake type pitch angle anisotropies suggesting that some of the discrete auroras are on closed field lines. Protons precipitate in both the discrete and the diffuse auroral region but do not contribute significantly to the total energy flux, except near the equatorward boundary of the diffuse aurora, where the proton flux can be dominant in some cases.