Electrodynamic structure of the late evening sector of the auroral zone
Electrodynamic structure of the late evening sector of the auroral zone
复制标题
极光带傍晚扇区的电动力结构
DOI：
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
S. Lai
中科院分区：
文献类型：
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作者：
W. J. Burke;D. Hardy;F. Rich;M. Kelley;M. Smiddy;B. Shuman;R. Sagalyn;R. P. Vancour;P.J.L. Widman;S. Lai
详细的观测从一个深夜部门通过的S3-2在北方极光区，并与几乎同时DMSP图像进行比较。给出了电场、磁场、高能电子（80 eV ≤E ≤17 keV）和热等离子体探测器的高时间分辨测量结果。扩散极光区的特征是几乎各向同性的电子通量和缓慢变化（≤20 mV/m）的电场。该地区的伯克兰电流主要进入电离层，并带有嵌入的狭窄的向上电流片。同步磁强计和卫星电位波动表明，向上的电流片是真实的，这些向上的电流可能是由沉淀，低能等离子体片电子。在扩散极光的极向，对流电场的大小变化很快，与沉淀电子的强度有关。在可见电弧上方观察到倒V型结构。在弧的赤道边缘附近发现了一个强烈的向下电流片（>10 µA/m²）。在这个地方的电离层热等离子体是接近边缘稳定的O+离子回旋湍流的开始。平行于B的电场分量为10 mV/m的测量在这个区域的强向下电流。弧附近的等离子体和电场分布表明，极光电喷流分布在扩散极光区，但最强烈的极光弧的赤道边界附近。
Detailed observations from a late evening sector pass of S3-2 over the northern auroral zone are presented and compared with nearly simultaneous DMSP imagery. High time resolution measurements are presented from electric field, magnetic field, energetic electron (80 eV ≤E ≤17 keV), and thermal plasma detectors. The region of diffuse aurorae was characterized by nearly isotropic electron fluxes and slowly varying (≤20 mV/m) electric fields. The Birkeland currents in this region were predominantly into the ionosphere with embedded, narrow sheets of upward currents. Simultaneous magnetometer and satellite potential fluctuations show that the upward current sheets are real and that these upward currents are probably carried by precipitating, low-energy plasma sheet electrons. Poleward of the diffuse aurorae, the covective electric field varied rapidly in magnitude, anticorrelating with the intensity of precipitating electrons. An inverted-V structure was observed above a visible arc. An intense downward current sheet (>10 µA/m²) was found near the equatorward edge of the arc. At this place the ionospheric thermal plasma was near marginal stability for the onset of O+ ion cyclotron turbulence. An electric field component parallel to B of ∼10 mV/m was measured in this region of strong downward current. The plasma and electric field distributions in the vicinity of the arc suggest that the auroral electrojet was distributed over the region of diffuse auroral but was most intense near the equatorward boundary of the auroral arc.