Observations of field‐aligned currents in association with strong convection electric fields at subauroral latitudes
Observations of field‐aligned currents in association with strong convection electric fields at subauroral latitudes
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DOI：
10.1029/ja085ia05p02335
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发表时间：
1980-05
影响因子：
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通讯作者：
F. Rich;W. J. Burke;M. Kelley;M. Smiddy
中科院分区：
文献类型：
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作者：
F. Rich;W. J. Burke;M. Kelley;M. Smiddy
根据1976年S3-2卫星的资料，对极光带赤道方向的强对流电场（E >50 mV/m）区进行了研究。只发现了7个实例，这表明即使在考虑到数据覆盖面方面的差距之后，发生率也很低。虽然这种现象与Kp或AE的大小无关，但它总是与亚暴有关。电场和磁场的数据表明，电场产生的等离子体片离子被驱动更接近地球比等离子体片电子的磁层对流在傍晚部门。通过该区域进入电离层的净场向电流的存在表明存在纬向电导率梯度。在强场向电流（≥1 µA/m²）区域附近的电离层粒子耗尽进入电离层，表明向上移动的电离层电子正在携带电流。Banks和Yasuhara（1978）提出的电场开始后约1分钟E区的疏散没有得到数据的支持，但它可能发生在10 - 30分钟的时间尺度上。如果F区和E区都在强对流区耗尽，结果可能是电离层中自然出现的“洞”。
An examination of regions of strong convection electric fields (E >50 mV/m) equatorward of the auroral zone has been made on the basis of data from the S3-2 satellite in 1976. Only seven examples were found, which indicates a low occurrence rate even after accounting for the gaps in data coverage. While this phenomenon did not correlate with the magnitude of Kp or AE, it is always substorm related. The electric field and magnetic field data indicate that the electric field is generated by plasma sheet ions being driven closer to the earth than plasma sheet electrons by magnetospheric convection in the evening sector. The existence of a net field-aligned current into the ionosphere through the region indicates the presence of latitudinal conductivity gradient. The depletions of ionospheric particles near regions of strong field-aligned currents (≥1 µA/m²) into the ionosphere indicate that upward moving ionospheric electrons are carrying the current. The evacuation of the E region approximately 1 min after the onset of the electric field as suggested by Banks and Yasuhara (1978) is not supported by the data, but it may occur on a time scale of ∼30 min. If both the F region and E region are depleted in the strong convection region, the result may be a naturally occurring ‘hole’ in the ionosphere.