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Unveiling the timescales and intensities of solar-terrestrial interactions using novel datasets and techniques

使用新颖的数据集和技术揭示日地相互作用的时间尺度和强度

基本信息

批准号：
ST/V004883/1
负责人：
John Coxon
金额：
$ 60.43万
依托单位：
Northumbria University
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2022
资助国家：
英国
起止时间：
2022 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FV004883%2F1
关键词：
Unveiling timescales intensities solar terrestrial

项目摘要

My research will quantify the Earth's reaction to the solar wind, a continuous stream of particles which comes from the Sun and carries magnetic fields with it. The region of space containing Earth's own magnetic field is known as the magnetosphere, and the magnetic fields and particles in the solar wind interact with the edge of the magnetosphere, which is called the magnetopause. The interactions which occur at the magnetopause are communicated to a region of Earth's atmosphere called the ionosphere (at an altitude of just above 100 km) by electrical currents which flow along Earth's magnetic field, called Birkeland currents. These currents flow in reaction to triggers from the magnetopause and within the magnetosphere, in turn causing potentially dangerous geomagnetic effects on the surface of Earth, like damaging satellites or knocking out power and telecoms infrastructure.Two types of event which cause enhanced current flow and thus can cause potentially dangerous effects are geomagnetic storms and substorms. Geomagnetic storms are multi-day events which occur when the solar wind drives a lot of activity at the magnetopause and this in turn causes large currents to flow through the system over a period of days. Substorms are events on hourly timescales which occur in the Earth's magnetosphere and drive large currents in specific areas of Earth's magnetosphere for a shorter period of time. The correspondence between these two events is not well-understood. Furthermore, we do not know whether substorms start far from Earth and cause effects which move towards it, or whether they start close to Earth and cause effects that move away. I will find out which of these things is happening by using techniques originally developed to look at the centres of galaxies. Understanding these events, as well as understanding when the largest currents flow, is vital to understanding how the Sun can disrupt and destroy our infrastructure on Earth.Another important avenue of research is understanding how efficient the response to these events is. We need to know how well the ionosphere can conduct current in different situations as well as how the currents flow differently in the Northern and Southern Hemisphere. During my PhD, I discovered the hemispheric asymmetry in Birkeland current, and one of the questions I will answer (by examining many other datasets alongside modelled results) is where this hemispheric asymmetry comes from. This means I can deduce how the amount of current that can flow is different in different conditions and places on Earth's surface, which will in turn allow us much better insights into how these currents can lead to problems for us on the surface.My research programme will answer key questions we have about the topics above and will significantly advance our knowledge of the Birkeland currents. I will study the currents using a constellation of 66 spacecraft from the Iridium constellation, which orbit the Earth 780 km above the surface. Magnetometers to measure the magnetic field at these spacecraft, and then physical equations are used to derive the Birkeland current from those measurements. I am one of the foremost international researchers using this dataset, which is called AMPERE, and so I am very well-suited to using this data to answer questions we have about the Birkeland currents.

我的研究将量化地球对太阳风的反应。太阳风是来自太阳并携带磁场的连续粒子流。包含地球磁场的空间区域被称为磁层，太阳风中的磁场和粒子与磁层边缘相互作用，称为磁层顶。发生在磁层顶的相互作用通过沿着地球磁场流动的电流（称为伯克兰电流）传递到地球大气层的一个称为电离层的区域（高度略高于100公里）。这些电流会对磁层顶和磁层内的触发做出反应，从而对地球表面造成潜在的危险地磁效应，例如损坏卫星或摧毁电力和电信基础设施。两种类型的事件会导致电流增强，从而可能造成潜在的危险影响，即地磁暴和亚磁暴。地磁暴是一种多日事件，当太阳风在磁层顶驱动大量活动时发生，这反过来又导致大电流在一段时间内流过系统。亚暴是发生在地球磁层中的每小时时间尺度的事件，并在较短的时间内在地球磁层的特定区域驱动大电流。这两个事件之间的对应关系还不很清楚。此外，我们不知道亚暴是从远离地球的地方开始并导致向地球移动的影响，还是从靠近地球的地方开始并导致远离地球的影响。我将通过使用最初开发用于观察星系中心的技术来找出这些事情中的哪一个正在发生。了解这些事件，以及了解最大电流的流动时间，对于了解太阳如何干扰和破坏我们在地球上的基础设施至关重要。另一个重要的研究途径是了解对这些事件的反应有多有效。我们需要知道电离层在不同情况下传导电流的能力，以及电流在北方和南半球的流动方式。在我的博士学位期间，我发现了Birkeland电流的半球不对称性，我将回答的问题之一（通过检查许多其他数据集以及建模结果）是这种半球不对称性来自哪里。这意味着我可以推断出在地球表面不同的条件和地方，电流的大小是如何不同的，这反过来又会让我们更好地了解这些电流是如何给我们带来问题的。我的研究计划将回答我们对上述主题的关键问题，并将大大提高我们对伯克兰电流的认识。我将使用来自铱星座的66个航天器的星座来研究电流，该星座在地球表面780公里处绕地球运行。磁力计测量这些航天器的磁场，然后使用物理方程从这些测量结果中推导出Birkeland电流。我是使用这个数据集的最重要的国际研究人员之一，这个数据集被称为AMPERE，所以我非常适合使用这些数据来回答我们关于伯克兰电流的问题。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Extreme Birkeland Currents Are More Likely During Geomagnetic Storms on the Dayside of the Earth

在地球白天的地磁风暴期间更有可能出现极端伯克兰电流

DOI：
10.1029/2023ja031946
发表时间：
2023
期刊：
Space Physics
影响因子：
0
作者：
Coxon J
通讯作者：
Coxon J

Distributions of Birkeland Current Density Observed by AMPERE are Heavy-Tailed or Long-Tailed

AMPERE 观测到的伯克兰电流密度分布为重尾或长尾

DOI：
10.1029/2021ja029801
发表时间：
2022
期刊：
Space Physics
影响因子：
0
作者：
Coxon J
通讯作者：
Coxon J

Response timescales of the magnetotail current sheet during a geomagnetic storm: Global MHD simulations

DOI：
10.3389/fspas.2022.966164
发表时间：
2022-09
期刊：
影响因子：
0
作者：
J. Eggington;J. Coxon;R. Shore;R. Desai;L. Mejnertsen;J. Chittenden;J. Eastwood
通讯作者：
J. Eggington;J. Coxon;R. Shore;R. Desai;L. Mejnertsen;J. Chittenden;J. Eastwood

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