Reconstruction of the magnetic field, electric current, and plasma pressure is provided using a new data mining (DM) method with weighted nearest neighbors (NN) for strong storms with the storm activity index Sym‐H < −300 nT, the Bastille Day event (July 2000), and the 20 November 2003 superstorm. It is shown that the new method significantly reduces the statistical bias of the original NN algorithm toward weaker storms. In the DM approach the magnetic field is reconstructed using a small NN subset of the large historical database, with the subset number K_NN ≫ 1 being still much larger than any simultaneous multiprobe observation number. This allows one to fit with observations a very flexible magnetic field model using basis function expansions for equatorial and field‐aligned currents, and at the same time, to keep the model sensitive to storm variability. This also allows one to calculate the plasma pressure by integrating the quasi‐static force balance equation with the isotropic plasma approximation. For strong storms of particular importance becomes the resolution of the eastward current, which prevents the divergence of the pressure integral. It is shown that in spite of the strong reduction of the dominant NN number in the new weighted NN algorithm to capture strong storm features, it is still possible to resolve the eastward current and to retrieve plasma pressure distributions. It is found that the pressure peak for strong storms may be as close as ≈2.1R_E to Earth and its value may exceed 300 nPa.

中文翻译：

---

重构极端地磁风暴：打破数据匮乏的诅咒

 巴士底日事件使用暴风活动指数Sym-H  <-300 nT的强风暴，采用加权近邻加权（NN）的新数据挖掘（DM）方法对磁场，电流和等离子压力进行重建。（2000年7月）和2003年11月20日的超级风暴。结果表明，该新方法大大降低了原始NN算法对较弱风暴的统计偏差。在DM方法中，使用大型历史数据库的一个小NN子集重建磁场，子集号K _{N N≫}  1仍然比任何同时进行的多探针观测数大得多。这使得人们可以使用基本函数扩展来适应赤道和磁场对准电流的非常灵活的磁场模型，同时保持模型对风暴变化的敏感性。这也使人们可以通过将准静态力平衡方程与各向同性等离子体近似值相集成来计算等离子体压力。对于特别重要的强风暴，将成为东流的分辨率，这可以防止压力积分的发散。结果表明，尽管在新的加权NN算法中捕获的主要NN数已大大减少以捕获强大的风暴特征，但仍然有可能解析出东流并恢复等离子体压力分布。≈ 2.1 - [R _ë地球并且它的值可能超过300 NPA。