Coupled‐mode scenario for the magnetospheric dynamics
Coupled‐mode scenario for the magnetospheric dynamics
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DOI：
10.1029/95ja03192
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发表时间：
1996-06
期刊：
影响因子：
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通讯作者：
V. A. Sergeev;T. Pulkkinen;R. Pellinen
中科院分区：
文献类型：
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作者：
V. A. Sergeev;T. Pulkkinen;R. Pellinen
亚暴现象进行了审查，重点放在磁层源区的发病，对形态的初始分裂和随后的激活，并对个别亚暴的变量字符。我们提供的证据表明，在亚暴发生之前，在随后的激活过程中，在准偶极和尾状磁场区域之间的界面处形成了一个强烈的薄电流片。我们推断，最初的分裂，随后的多次激活，假分裂，和其他短期激活在非亚暴时间都是相似的形态，并有相同的形成机制。我们假设能量耗散的基本单位，脉冲耗散事件，这是本地化的空间，并有一个很短的寿命为10.1分钟，是尾部重联的表现。我们还强调了以前的作者提出的支持这种时间依赖性和本地化的证据。基于上述，我们认为在亚暴和非亚暴时间有两个基本的磁层过程负责能量储存和耗散：一个全球性的和缓慢的准静态尾部重新配置负责能量储存，以及一系列局部的，零星的，短期的能量耗散事件。这些竞争过程大多数时候可以在等离子体片的某些部分观察到;它们的相对强度决定了大尺度动力学演化的类型。在这种情况下，各种动态情况被解释为两个竞争过程之间平衡的变化。
Substorm phenomena are reviewed with emphasis on the magnetospheric source region of the onset, on the morphology of the initial breakup and subsequent activations, and on the variable character of individual substorms. We provide evidence that before the substorm onset and during the following activations an intense, thin current sheet is formed at the interface between the quasi‐dipolar and taillike magnetic field regions. We infer that the initial breakup, the following multiple activations, pseudobreakups, and other short‐term activations during nonsubstorm times are all similar in morphology and have the same formation mechanism. We postulate that the elementary units of energy dissipation, impulsive dissipation events, which are localized in space and have a short lifetime of ∼1 min, are the manifestations of tail reconnection. We also emphasize the evidence that previous authors have presented in favor of this time dependence and localization. On the basis of the above, we suggest that there are two basic magnetospheric processes responsible for energy storage and dissipation during both substorm and nonsubstorm times: A global and slow quasi‐static tail reconfiguration responsible for the energy storage, and a sequence of local, sporadic, short‐term energy dissipation events. These competitive processes can be observed most the time in some part of the plasma sheet; their relative intensity determines the type of large‐scale dynamic evolution. In this scenario, the various dynamical situations are interpreted as variations in the balance between the two competing processes.