This paper describes insights into the nature of corotating plasmaspheric irregularities (CPIs) enabled by a newly developed method for range‐ and time‐resolved tomographic images of these structures. This was originally developed using high‐precision measurements of total electron content (TEC) gradients toward cosmic radio sources using an interferometric radio telescope, the Very Large Array (VLA). Here, the method has been adapted to work with TEC measurements from compact arrays of Global Positioning System (GPS) receivers in California and Hawaii. Because the VLA is much more sensitive to line‐of‐sight density fluctuations and the background density within the plasmasphere drops quickly with radial distance, the GPS‐based analysis has a much more limited range (maximum of ∼5,000 km with GPS versus ∼15,000 with the VLA). However, because the GPS arrays collect data continuously, they offer much more complete temporal coverage and range resolution. This enabled a thorough comparison between CPI behavior near solar maximum and that near solar minimum, which was not possible with the VLA. The solar minimum data largely agree with previously reported VLA‐based data, which were mostly confined to times near solar minimum. These indicated that the primary drivers of CPIs during these conditions are perturbations within the background electric field associated with so‐called electro‐buoyancy waves within the midlatitude ionosphere. However, the detection rates of and properties of CPIs were often markedly different near solar maximum. This points to different CPI drivers related to solar/geomagnetic activity such as substorms and/or the interchange instability at lower L ‐shells (∼3–4).

中文翻译：

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等离子球面不规则旋转的性质和成因：第二部分-紧凑型GPS接收机的层析成像

本文介绍了通过新开发的方法对这些结构的距离和时间分辨断层扫描图像实现的同向旋转等离子层不规则（CPI）性质的见解。它最初是使用干涉测量射电望远镜超大型阵列（VLA）高精度测量朝向宇宙无线电源的总电子含量（TEC）梯度而开发的。在这里，该方法已适用于处理来自加利福尼亚和夏威夷的全球定位系统（GPS）接收器紧凑阵列的TEC测量。由于VLA对视线密度波动更加敏感，并且等离子层内的背景密度随径向距离而迅速下降，因此基于GPS的分析范围更有限（GPS的最大距离为5,000 km，而5,000的最大距离为〜15,000）与VLA）。然而，由于GPS阵列连续收集数据，因此它们提供了更完整的时间覆盖范围和距离分辨率。这样就可以对接近日照最大值的CPI行为和接近日照最小值的CPI行为进行彻底的比较，而VLA则无法做到。太阳最低数据在很大程度上与以前报道的基于VLA的数据一致，后者主要限于接近太阳最低时间的时间。这些表明，在这种情况下，CPI的主要驱动力是与中纬度电离层内所谓的电浮力波有关的背景电场内的扰动。但是，在太阳最大值附近，CPI的检测率和CPI属性通常明显不同。这指出了与太阳/地磁活动有关的不同CPI驱动因素，例如亚暴雨和/或较低处的换乘不稳定性L壳（〜3-4）。