A statistical analysis of the properties of the plasma sheet in the geomagnetic tail using the ISEE 3 deep-tail data set is undertaken. The observed plasma sheet properties are compared to predictions of two models of reconnection. The first model [Cowley, 1980; Cowley and Southwood, 1980] is based on the balance of stress between a cold plasma inflow and the magnetic tension of reconnected field lines at the current sheet. The second [Owen et al., 1991] makes an attempt to incorporate heating of the plasma sheet population into this class of model. We find that only 60% of all plasma sheet events show densities greater than that in the adjacent lobe, as would be expected on the basis of mass conservation in the reconnection models. In addition, comparison of the distribution of the predicted velocities with the observed velocities shows that for a significant proportion of events, neither reconnection model accurately predicts the observed flows. In fact, the plasma sheet is most often seen to be in a quasi-stagnant state. During periods of tailward convection, the heated model appears the more appropriate for describing plasma sheet flow due to reconnection. However, in the case of the heated (simple) model, at least 50% (60%) of tailward flows are observed at velocities well below the predictions. These events also have positive B_z on average and may therefore be associated with the tailward transport of closed flux tubes. They are also associated with geomagnetically quiet times. Such events are seen at all distance between -60 and -240 R_E in the plasma sheet. These results strongly support previous suggestions that even at large downtail distances, the observed plasma sheet flows are often driven by processes other than reconnection. While the models correctly predict a significant proportion of the flow speeds for tailward flows, the earthward flow events are not well described by either model. In summary, 40% of the data set cannot be described by the reconnection models due to mass conservation requirements, and at most only 50% of the tailward flow speeds are in agreement with the predictions of these models. As such, only 30% of tailward flow events are well described by the models presented here.
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机译：使用ISEE 3深尾数据集对地磁尾部等离子体薄层的属性进行了统计分析。将观察到的等离子片特性与两种重新连接模型的预测值进行比较。第一个模型[Cowley，1980; Cowley和Southwood，1980年]是基于冷等离子体流入与当前表层重新连接的磁力线之间的磁张力之间的平衡。第二种[Owen et al。，1991]尝试将加热血浆片种群纳入此类模型。我们发现，只有60％的血浆薄层事件的密度大于相邻叶的密度，这是基于重新连接模型中的质量守恒所预期的。此外，将预测速度的分布与观察到的速度进行比较表明，对于很大比例的事件，两个重联模型都无法准确预测观察到的流量。实际上，最常看到等离子片处于准停滞状态。在向后对流期间，由于重新连接，加热的模型似乎更适合描述等离子流。但是，在加热（简单）模型的情况下，在远低于预测值的速度下观察到至少有50％（60％）的尾流。这些事件平均也具有正B_z，因此可能与封闭通量管的向后传输有关。它们还与地磁平静时期有关。在等离子片中的-60和-240 R_E之间的所有距离处都可以看到此类事件。这些结果有力地支持了先前的建议，即即使在较大的尾部距离处，观察到的等离子片流也经常由除重新连接以外的其他过程驱动。尽管这些模型正确地预测了向后流动的很大一部分流速，但是任何一个模型都没有很好地描述向地流动事件。总之，由于质量守恒的要求，重连接模型无法描述40％的数据集，并且最多只有50％的向后流动速度与这些模型的预测一致。这样，这里介绍的模型很好地描述了向后流动事件的30％。
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