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arXiv 2408.01778astro-ph.CO
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宇宙弦尾迹中的磁场放大与衰减

Magnetic field amplification and decay in cosmic string wakes

Indian Institute of Technology, Kanpur(坎普尔印度理工学院);School of Physics, University of Hyderabad(海得拉巴大学物理学院)

Deepanshu Bisht, Dilip Kumar, Soumen Nayak, Soma Sanyal

AI总结:

研究揭示了宇宙弦尾迹中磁场因流体流动和扰动长度尺度而发生放大与衰减的机制,为磁重联过程提供新见解。

摘要:

我们利用分析和数值方法,在运动宇宙弦的时空环境中对磁化等离子体中的涡旋形成进行了详细研究。宇宙弦周围的锥形时空导致冻结在其中的磁场因流体流动而变形。我们发现尾迹区域的过密度会放大磁场。这种放大取决于磁场扰动的方向和长度尺度。磁流体动力学的法拉第定理解释了这一结果。然而,我们的研究还表明,由于法拉第定理在一定长度尺度下失效,磁场可能根据扰动的长度尺度而衰减。该长度尺度是等离子体中带电粒子的回旋半径。我们的发现对理解宇宙弦尾迹中的磁重联具有重要意义。

英文摘要:

We do a detailed study on vortex formation in a magnetized plasma within the spacetime of a moving cosmic string using analytical and numerical methods. The conical spacetime around the cosmic string causes the frozen-in magnetic field to deform due to the fluid flow. We find that the overdensity in the wake region amplifies the magnetic field. This amplification depends on the direction and the lengthscale of the magnetic perturbations. Alfvens theorem of flux conservation explains this result. However, our study also shows that the magnetic field can decay depending on the perturbation lengthscale, due to the breakdown of Alfvens theorem at a certain lengthscale. This lengthscale is the gyroradius of the charged particles in the plasma. Our findings are significant for understanding magnetic reconnection in cosmic string wakes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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