Geomagnetically induced currents during the 07-08 September 2017 disturbed period: a global perspective
Geomagnetically induced currents during the 07-08 September 2017 disturbed period: a global perspective
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2017年9月7日至8日扰动期间的地磁感应电流：全球视角
DOI：
10.1051/swsc/2021014
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发表时间：
2021
影响因子：
3.3
通讯作者：
Clilverd M
中科院分区：
文献类型：
--
作者：
Clilverd M
分析了位于中纬度53°等高线附近的六个纵向分离的地磁观测站的测量结果。我们重点关注2017年9月7日和8日发生的大地磁扰动。结合现有的地磁感应电流（GIC）数据从两个变电站，每个位于附近的一个磁观测站，我们调查的磁层驱动程序的最大的事件。我们分析太阳风参数结合极光电喷流指数来探讨驱动机制。在中纬度地区观测到6次磁场扰动事件，dH/dt> 60 nT/min。在其中3次事件中，同位GIC测量确定了Transformer电流>15 A。最初的事件是由太阳风压力脉冲造成的，对向阳面的影响最大，与向阳面地磁场的快速压缩一致。其中四起事件是由亚暴引起的。每个亚暴驱动事件的最大影响的磁局部时间的变化是明显的，磁午夜，早晨和黄昏事件都发生了。这六次事件发生在近24小时的时间内，在此期间，太阳风保持在>700 km s−1的水平，表明在突然的风暴开始后，电力网络中潜在的GIC问题的时间尺度延长。这项工作展示了理解全球电力行业地面磁场变化（以及GIC幅度）的原因的挑战。它还表明，在考虑GIC对电网造成的全球危害时，磁地方时和不同的磁层内部过程非常重要。
Measurements from six longitudinally separated magnetic observatories, all located close to the 53° mid-latitude contour, are analysed. We focus on the large geomagnetic disturbance that occurred during 7 and 8 September 2017. Combined with available geomagnetically induced current (GIC) data from two substations, each located near to a magnetic observatory, we investigate the magnetospheric drivers of the largest events. We analyse solar wind parameters combined with auroral electrojet indices to investigate the driving mechanisms. Six magnetic field disturbance events were observed at mid-latitudes with dH/dt> 60 nT/min. Co-located GIC measurements identified transformer currents >15 A during three of the events. The initial event was caused by a solar wind pressure pulse causing largest effects on the dayside, consistent with the rapid compression of the dayside geomagnetic field. Four of the events were caused by substorms. Variations in the Magnetic Local Time of the maximum effect of each substorm-driven event were apparent, with magnetic midnight, morning-side, and dusk-side events all occurring. The six events occurred over a period of almost 24 h, during which the solar wind remained elevated at >700 km s−1, indicating an extended time scale for potential GIC problems in electrical power networks following a sudden storm commencement. This work demonstrates the challenge of understanding the causes of ground-level magnetic field changes (and hence GIC magnitudes) for the global power industry. It also demonstrates the importance of magnetic local time and differing inner magnetospheric processes when considering the global hazard posed by GIC to power grids.