Magnetic field amplification and decay in cosmic string wakes

Fuente: arXiv
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Auteurs principaux: Bisht, Deepanshu, Kumar, Dilip, Nayak, Soumen, Sanyal, Soma
Format: Preprint
Publié: 2024
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author Bisht, Deepanshu
Kumar, Dilip
Nayak, Soumen
Sanyal, Soma
author_facet Bisht, Deepanshu
Kumar, Dilip
Nayak, Soumen
Sanyal, Soma
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2408_01778
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Magnetic field amplification and decay in cosmic string wakes
Bisht, Deepanshu
Kumar, Dilip
Nayak, Soumen
Sanyal, Soma
Cosmology and Nongalactic Astrophysics
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.
title Magnetic field amplification and decay in cosmic string wakes
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2408.01778