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Quantifying magnetic fluxes and reconnection rates in complex fields

量化复杂场中的磁通量和重联率

基本信息

批准号：
ST/G002436/1
负责人：
Gunnar Hornig
金额：
$ 35.41万
依托单位：
University of Dundee
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FG002436%2F1
关键词：
Quantifying magnetic fluxes reconnection rates

项目摘要

The Sun's atmosphere, as well as the atmospheres of most stars, consists of a hot plasma which is structured by a complex magnetic field. At random intervals the structure of this magnetic field undergoes a sudden local change, a so-called magnetic reconnection event, which can trigger minor or major outbreaks of plasma. These outbreaks heat the atmosphere and release plasma from the solar atmosphere into the interplanetary space. It is suspected that these reconnection processes occur not in the form of individual events but more in the form of an avalanche, where an initial major event triggers a series of smaller reconnection events. However, we are unable to detect these with our current observational methods. This proposal aims to develop the theoretical tools to answer the fundamental question of whether reconnection occurs in form of a singular event or as an avalanche. One of the main goals is to identify the characteristic signature of magnetic reconnection. This 'fingerprint' of reconnection is given by a specific change in the structure of the field and can be quantified in terms of magnetic flux. In order to detect this fingerprint of reconnection in the observed magnetic fields on the Sun we have to analyse these also with respect to their structure and the magnetic fluxes involved. For this we must define certain measures, so-called topological fluxes, and the proposal aims to define these measures and provide algorithms for finding them in arbitrary magnetic fields. Eventually these will allow us to answer the main question as to whether magnetic reconnection occurs as an individual event or an avalanche. An answer to this question is not only of great interest to solar physics but also to other fields where similar plasmas are found such as in the atmospheres of other stars, in the turbulent plasma in accretion disks and the plasma in fusion devices.

太阳的大气层，以及大多数恒星的大气层，都是由一个复杂的磁场构成的热等离子体组成的。在随机的时间间隔内，这个磁场的结构会发生突然的局部变化，即所谓的磁重联事件，它可以触发等离子体的小规模或大规模爆发。这些爆发加热了大气层，并将等离子体从太阳大气层释放到行星际空间。人们怀疑这些重连过程不是以单个事件的形式发生的，而是以雪崩的形式发生的，在雪崩中，最初的重大事件引发了一系列较小的重连事件。然而，我们无法用我们目前的观测方法检测到这些。该提议旨在发展理论工具来回答重连是否以单一事件或雪崩的形式发生的基本问题。其中一个主要目标是识别磁场重联的特征信号。这种重联的“指纹”是由磁场结构的特定变化给出的，可以用磁通量来量化。为了在太阳上观测到的磁场中检测这种重联指纹，我们还必须分析它们的结构和所涉及的磁通量。为此，我们必须定义某些措施，所谓的拓扑通量，该提案的目的是定义这些措施，并提供算法，找到他们在任意磁场。最终，这些将使我们能够回答主要问题，即磁重联是作为一个单独的事件还是雪崩发生的。这个问题的答案不仅对太阳物理学非常感兴趣，而且对其他领域也非常感兴趣，在其他恒星的大气层中，在吸积盘中的湍流等离子体和聚变装置中的等离子体中发现了类似的等离子体。