How do weak shocks accelerate high energy particles?

弱激波如何加速高能粒子？

• 批准号: ST/R003246/2
• 负责人: David Long
• 金额: $ 14.92万
• 依托单位: Queen's University Belfast
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FR003246%2F2
• 关键词: How; do; weak; shocks; accelerate

Shock waves are found everywhere in the Universe and are one of the most efficient ways of accelerating particles like protons and electrons. However, the conditions required to produce those shocks and accelerate particles are so extreme that they're impossible to recreate on Earth. As a result, we still don't know a lot about how these shocks accelerate particles or how they're affected by things like density or magnetic field. Most of the shocks that produce these very high energy particles are also incredibly far away in other galaxies, making them difficult to study properly. For example, while we can see a supernova shock using astronomical telescopes, it's really hard to then identify and study the particles it accelerates.However, the Earth is located close to a natural laboratory with extreme density, temperature and magnetic field variations which regularly produces large-scale shocks that shower us with energetic particles; the Sun. We have a fleet of spacecraft returning constant observations of the Sun, allowing us to see in near-real-time the sudden release of stored magnetic energy in the solar atmosphere (also called the corona). This energy release can produce bursts of radiation that we call solar flares, hurl massive bubbles of plasma called coronal mass ejections into the solar system towards the Earth and launch vast global shock waves that can travel across the Sun in under an hour. Although these shocks are so much weaker than supernovae that they shouldn't be able to accelerate any particles, they regularly produce billions of energetic particles that we can almost immediately detect at Earth. These particles can be fatal for satellites orbiting the Earth, blinding them and causing them to fail, with knock-on effects for GPS and telecommunications. With my research, I'm trying to understand why these really weak shocks occur, how they accelerate particles to incredibly high energies and how those energetic particles affect the Earth and the near-Earth environment.The Sun offers a unique opportunity to study both extreme shocks and the particles that they accelerate at the same time in unprecedented detail; we can see what happens and "touch" the resulting particles, which is something that you can't do in any other field of astrophysics. Everything about this situation is also very counterintuitive; the Sun is a pretty average star producing very weak shocks that shouldn't be able to accelerate any particles yet it manages to accelerate particles to incredibly high energies. How this happens is still an open question, and one that has implications not just for our understanding of the Sun, but also for fundamental plasma physics and space weather. If we know how this process works we might be able to predict it, which will help us to protect vulnerable spacecraft and infrastructure on Earth. On a more personal level though, working on this topic really hammers home the differences between how calm the Sun is when you look at it from the ground versus the violently active Sun producing solar eruptions which we see from space, which I just think is fascinating.

冲击波在宇宙中到处都是，是加速质子和电子等颗粒的最有效方法之一。但是，产生这些冲击和加速颗粒所需的条件是如此极端，以至于它们不可能在地球上重现。结果，我们仍然不知道这些冲击如何加速粒子或如何受到密度或磁场之类的影响。产生这些非常高能量颗粒的大多数冲击在其他星系中也非常遥远，这使得它们难以正确学习。例如，尽管我们可以使用天文望远镜看到超新星冲击，但确实很难识别和研究它加速的颗粒。太阳。我们有一支航天器的机队，返回太阳的持续观察，使我们能够在太阳大气中（也称为Corona）在近实时释放储存的磁能突然释放。这种能量释放会产生我们称为太阳耀斑的辐射爆发，吹出了称为冠状体质量弹出的巨大等离子体的气泡进入太阳系向地球，并引发了巨大的全球冲击波，可以在一个小时内在一个小时内越过太阳。尽管这些冲击比超新星弱得多，因此它们应该无法加速任何颗粒，但它们经常产生数十亿个能量颗粒，我们几乎可以立即在地球上检测到。这些颗粒对于绕地球的卫星来说可能是致命的，使它们蒙蔽并导致它们失败，并具有对GPS和电信的连锁反应。通过我的研究，我试图理解为什么这些真正弱的冲击发生，它们如何加速颗粒到令人难以置信的高能量以及这些能量颗粒如何影响地球和近地环境。太阳为研究极端冲击和它们同时在不前所未有的细节中同时加速的极端冲击和颗粒提供了独特的机会；我们可以看到会发生什么并“触摸”所得粒子，这是您在任何其他天体物理学领域都无法做的事情。关于这种情况的一切也非常违反直觉；太阳是一颗相当普通的恒星，产生非常弱的冲击，应该无法加速任何颗粒，但它设法将颗粒加速到令人难以置信的高能量。这种情况的发生仍然是一个悬而未决的问题，它不仅对我们对太阳的理解，而且对基本的等离子体物理和太空天气有影响。如果我们知道这个过程是如何工作的，我们可以预测它，这将有助于我们保护地球上脆弱的航天器和基础设施。但是，从更个人的角度来看，从地面看阳光与猛烈活跃的太阳产生太阳爆发时，从太空中看到的太阳时，太阳的平静之间的差异确实使我们觉得很着迷。

项目成果

Slow solar wind sources High-resolution observations with a quadrature view

慢速太阳风源 具有正交视图的高分辨率观测

• DOI: 10.1051/0004-6361/202345983
• 发表时间: 2023
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: Barczynski K

The source of unusual coronal upflows with photospheric abundance in a solar active region

太阳活动区域光球丰度异常的日冕上升流的来源

• DOI: 10.1051/0004-6361/202245747
• 发表时间: 2023
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: Harra L

Extreme-ultraviolet fine structure and variability associated with coronal rain revealed by Solar Orbiter/EUI HRI EUV and SPICE

太阳轨道飞行器/EUI HRI EUV 和 SPICE 揭示了与日冕雨相关的极紫外精细结构和变化

• DOI: 10.1051/0004-6361/202346016
• 发表时间: 2023
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: Antolin P

Observational Evidence of S-web Source of the Slow Solar Wind

• DOI: 10.3847/1538-4357/acc653
• 发表时间: 2023-03
• 期刊: The Astrophysical Journal
• 作者: D. Baker;P. Démoulin;S. Yardley;T. Mihailescu;L. Driel-Gesztelyi;R. D’Amicis;D. Long;A. To;C. Owen;T. Horbury;D. Brooks;D. Perrone;R. French;A. James;M. Janvier;S. Matthews;M. Stangalini;G. Valori;P. Smith;R. A. Cuadrado;H. Peter;U. Schuehle;L. Harra;Krzysztof Barczynski;D. Berghmans;A. Zhukov;L. Rodriguez;C. Verbeeck

First perihelion of EUI on the Solar Orbiter mission

太阳轨道飞行器任务中 EUI 的首次近日点

• DOI: 10.1051/0004-6361/202245586
• 发表时间: 2023
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: Berghmans D