Statistical description of coalescing magnetic islands via magnetic reconnection
| Autor: | Muni Zhou, David H. Wu, Nuno F. Loureiro, Dmitri A. Uzdensky |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
High Energy Astrophysical Phenomena (astro-ph.HE)
FOS: Physical sciences Condensed Matter Physics 01 natural sciences Space Physics (physics.space-ph) Physics - Plasma Physics Plasma Physics (physics.plasm-ph) Physics - Space Physics 0103 physical sciences Physics::Space Physics Computer Science::Programming Languages 010306 general physics Astrophysics - High Energy Astrophysical Phenomena 010303 astronomy & astrophysics |
| Popis: | The physical picture of interacting magnetic islands provides a useful paradigm for certain plasma dynamics in a variety of physical environments, such as the solar corona, the heliosheath, and the Earth's magnetosphere. In this work, we derive an island kinetic equation to describe the evolution of the island distribution function (in area and in flux of islands) subject to a collisional integral designed to account for the role of magnetic reconnection during island mergers. This equation is used to study the inverse transfer of magnetic energy through the coalescence of magnetic islands in 2D. We solve our island kinetic equation numerically for three different types of initial distribution: delta-distribution, Gaussian and power-law distribution. The time evolution of several key quantities is found to agree well with our analytical predictions: magnetic energy decays as $\tilde t^{-1}$, the number of islands decreases as $\tilde t^{-1}$, and the averaged area of islands grows as $\tilde t$, where $\tilde t$ is the time normalized to the characteristic reconnection time scale of islands. General properties of the distribution function and the magnetic energy spectrum are also studied. 38 pages; 10 figures; Accepted by Journal of Plasma Physics |
| Databáze: | OpenAIRE |
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