Characteristics of pseudobreakups and substorms observed in the ionosphere, at the geosynchronous orbit, and in the midtail
Characteristics of pseudobreakups and substorms observed in the ionosphere, at the geosynchronous orbit, and in the midtail
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电离层、地球同步轨道和中尾观测到的伪破碎和亚暴的特征
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
G. Reeves
中科院分区：
文献类型：
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作者：
A. Aikio;V. Sergeev;M. Shukhtina;L. Vagina;V. Angelopoulos;G. Reeves
我们利用光、磁和非相干散射雷达测量、两颗地球同步卫星的高能粒子和位于XGSM∼−86RE的GeoTail航天器的粒子和场数据，对两个亚暴和多个假爆发序列进行了全面的研究。按照常规命名法，我们将极光破裂中没有明显向极扩展(磁纬2°)的现象归类为假破裂。亚暴破裂后的极光增强也被观测到，并分别进行了分类。在纵向范围(当地时间1.3至6.1小时)或持续时间(5至16分钟)上，假风暴破裂与亚暴破裂没有差别。一般而言，在亚暴期间，产生地面磁扰动的电离层电流比假暴更强烈。我们发现，伪爆与亚暴破裂有相同的磁层过程，包括电流楔形形成、中纬度磁场Pi2脉动和地球同步高度的高能粒子注入。此外，伪爆发与近地区域的磁重联有关，典型的随后在GeoTail探测到的等离子体团就证明了这一点。这意味着受伪爆影响的磁尾体积在径向距离上相当大。我们的结论是，在伪暴和亚暴之间没有明确的定性区别，但在小的伪暴和大的亚暴之间存在状态的连续体。
We present a comprehensive study of a sequence of two substorms and multiple pseudobreakups using optical, magnetic and incoherent scatter radar measurements, energetic particles from two geosynchronous satellites and particle and field data from the Geotail spacecraft located at Xgsm ∼ −86 RE. Following conventional nomenclature, we classified as pseudobreakups those auroral breakups which did not exhibit significant poleward expansion (< 2° magnetic latitude). Auroral intensifications following substorm breakups were also observed, and were classified separately. Pseudobreakups were found not to differ from substorm breakups in longitudinal extent (from 1.3 to 6.1 hours of magnetic local time), or in duration (from 5 to 16 minutes). In general, the ionospheric currents producing ground magnetic disturbances were more intense during substorms than pseudobreakups. We found that pseudobreakups are associated with the same magnetospheric processes as substorm breakups which involve current wedge formation, midlatitude magnetic Pi2 pulsations and energetic particle injections at the geosynchronous altitude. Moreover, pseudobreakups are associated with magnetic reconnection in the near-Earth region, evidenced by the typical subsequent detection of a plasmoid at Geotail. This implies that the magnetotail volume influenced by a pseudobreakup is quite large in radial distance. We conclude that there is no definitive qualitative distinction between pseudobreakups and substorms but there is a continuum of states between the small pseudobreakups and large substorms.