Investigating the Drivers of Geomagnetically Induced Currents

研究地磁感应电流的驱动因素

• 批准号: NE/W006766/1
• 负责人: Suzanne Imber
• 金额: $ 53.23万
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FW006766%2F1
• 关键词: Investigating; Drivers; Geomagnetically; Induced; Currents

The Earth's magnetic field sits within the changeable, dynamic environment of the solar wind. The interaction of the two regimes drives rapid reconfigurations of the Earth's field, which induce currents to flow in conductors on the ground. These Geomagnetically Induced Currents (GICs) can be 10s to 100s of Amps, and can cause transformer heating and higher harmonics in power grids, degradation to metal pipelines, and signalling malfunctions on railway systems. The Lloyd's of London 2013 Space Weather report concluded that a once-in-a-Century event 'would cause major disruption to transport, food supplies, emergency and hospital services amongst other things...The absence of such fundamental services could lead to major and widespread social unrest, riots and theft with ramifications for the insurance industry and society in general'. The cost of such an event to the UK has been estimated at £0.9-15.9 billion, and while such huge events are rare, smaller, damaging, events are routinely observed.The key to predicting the location and magnitude of GICs is understanding the chain of causality from the Sun to the Earth's surface, and having instrumentation in key locations to make the measurements required for forecasting. Typical solar wind structures that drive powerful GICs have been identified, and can provide some early warning of extreme dynamics in the Earth's system. The other end of the chain, inducing currents in conductors on the ground due to a variable magnetic field, may be addressed through the application of Faraday's Law, given the conductivity of the local regolith, and the conductivity, length and orientation of the conductor. Typically, this research is funded by individual nations focussing on operational risk to their own critical infrastructure, and therefore the global picture is less well understood. The missing link required for accurate GIC forecasting is the physics of the central part of the chain: understanding how the highly dynamic ionospheric current systems generate the geomagnetic disturbances that drive GICs measured in infrastructure, thus enabling the coupling of existing solar wind/magnetosphere models with ground-based conductivity maps.We will use data from ground-based magnetometers (>200 stations) spread across every continent, to determine the location, timing and intensity of all geomagnetic disturbances over an eight-year period (2010-2017). These signatures will be related to their ionospheric drivers using a constellation of 66 satellites in low-Earth orbit which provide continual 2-minute snapshots of the magnetic energy stored in the system during this time period, and accurately characterise the location, direction and magnitude of the ionospheric current systems. The novelty of this approach is combining these two data sets for the first time to allow a global, statistical analysis over an entire solar maximum period.We will largely focus on high latitude regions (including northern Europe, Canada and the northern United States) where the most intense GICs are observed. Our work is relevant to space weather service providers (such as the UK Met Office), the energy and rail industries, and governments who monitor risk to critical infrastructure, as well as for future infrastructure planning. We will also study equatorial and mid-latitude disturbances, as these have the potential to disrupt infrastructure supporting major population centres, and the combination of equatorial and higher-latitude events could be highly damaging to infrastructure on a continental scale (such as in South America). This work will be a pathfinder for the feasibility of nowcasting, and perhaps even forecasting, of GICs, using acombination of existing satellite networks and solar wind monitors.

地球的磁场位于太阳风多变的动态环境中。这两种状态的相互作用驱动地球磁场的快速重新配置，从而诱导电流在地面上的导体中流动。这些地磁感应电流（GIC）可以是10 s到100 s安培，并且可以导致电网中的Transformer加热和高次谐波、金属管道的退化以及铁路系统的信号故障。劳合社伦敦2013年太空天气报告得出结论，百年一遇的事件“将对交通、食品供应、紧急情况和医院服务等造成重大中断.缺乏这些基本服务可能导致重大和广泛的社会动荡、骚乱和盗窃，对保险业和整个社会产生影响。这种事件对英国的损失估计为9亿至159亿英镑，虽然这种巨大的事件是罕见的，但较小的破坏性事件是经常观察到的。预测GIC的位置和大小的关键是了解从太阳到地球表面的因果关系链，并在关键位置配备仪器进行预测所需的测量。驱动强大GIC的典型太阳风结构已经确定，可以提供地球系统极端动态的一些早期预警。考虑到当地风化层的导电性以及导体的导电性、长度和方向，链的另一端由于可变磁场而在地面上的导体中感应电流，可以通过应用法拉第定律来解决。通常情况下，这项研究是由个别国家资助的，专注于本国关键基础设施的运营风险，因此对全球情况的了解较少。准确预测GIC所需的缺失环节是链条中心部分的物理特性：了解高度动态的电离层电流系统如何产生驱动基础设施中测量的GIC的地磁扰动，从而使现有的太阳风/磁层模型与地面电导率图相耦合。（>200个台站）分布在每个大陆，以确定八年期间（2010-2017年）所有地磁扰动的位置、时间和强度。这些特征将与其电离层驱动器相关，使用低地球轨道上66颗卫星组成的星座，这些卫星在此期间提供系统中储存的磁能的连续两分钟快照，并准确地确定电离层电流系统的位置、方向和大小。这种方法的新奇在于首次将这两个数据集结合起来，以便对整个太阳活动极大期进行全球统计分析。我们将主要关注高纬度地区（包括北方欧洲，加拿大和北方美国），这些地区观测到最强烈的GIC。我们的工作与空间气象服务提供商（如英国气象局），能源和铁路行业以及监控关键基础设施风险的政府以及未来基础设施规划有关。我们还将研究赤道和中纬度扰动，因为这些扰动有可能破坏支持主要人口中心的基础设施，赤道和高纬度事件的结合可能对大陆规模的基础设施造成严重破坏（例如在南美洲）。这项工作将是利用现有卫星网络和太阳风监测器相结合进行GIC临近预报甚至预报的可行性的探索者。

项目成果

Solar Wind-Magnetosphere Coupling During High-Intensity Long-Duration Continuous AE Activity (HILDCAA)

高强度长时间连续 AE 活动期间的太阳风-磁层耦合 (HILDCAA)

• DOI: 10.1029/2023ja032027
• 发表时间: 2023
• 期刊: Space Physics
• 作者: Milan S

Solar Cycle and Solar Wind Dependence of the Occurrence of Large dB / dt Events at High Latitudes

高纬度地区大 dB/dt 事件发生的太阳周期和太阳风依赖性

• DOI: 10.1029/2022ja030953
• 发表时间: 2023
• 期刊: Journal of Geophysical Research: Space Physics
• 作者: Milan, S. E.;Imber, S. M.;Fleetham, A. L.;Gjerloev, J.
• 通讯作者: Gjerloev, J.