A Model for Cosmic Magnetic Field Amplification: Effects of Pressure Anisotropy Perturbations
Magnetic field amplification in the early universe is a long-standing problem that has been extensively studied through theoretical and numerical approaches, focusing on turbulent dynamos and the growth of collisionless plasma instabilities. In the post-recombination era, pressure anisotropy drives...
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MDPI AG
2024-12-01
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| Online Access: | https://www.mdpi.com/2218-1997/11/1/9 |
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| author | Ji-Hoon Ha |
| author_facet | Ji-Hoon Ha |
| author_sort | Ji-Hoon Ha |
| collection | DOAJ |
| description | Magnetic field amplification in the early universe is a long-standing problem that has been extensively studied through theoretical and numerical approaches, focusing on turbulent dynamos and the growth of collisionless plasma instabilities. In the post-recombination era, pressure anisotropy drives plasma instabilities, and magnetic field amplification through these instabilities can be faster than that driven by turbulent dynamos. By considering the balance between isotropization through magnetic field amplification and anisotropy generation by external sources such as turbulence and anisotropic cosmic-ray scattering, it is reasonable to assume that the system evolves around an equilibrium anisotropy value. To improve the theoretical modeling of magnetic field amplification in such systems, this study specifically examines pressure anisotropy perturbations near the equilibrium anisotropy value, which may destabilize the system. By analyzing the effects of pressure anisotropy perturbations and their damping rates on the time evolution of cosmic magnetic fields, we highlight the importance of these perturbations in driving plasma instabilities and boosting cosmic magnetic field amplification. |
| format | Article |
| id | doaj-art-786aec9daca0452e964f9899e58fc66e |
| institution | Kabale University |
| issn | 2218-1997 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Universe |
| spelling | doaj-art-786aec9daca0452e964f9899e58fc66e2025-01-24T13:51:28ZengMDPI AGUniverse2218-19972024-12-01111910.3390/universe11010009A Model for Cosmic Magnetic Field Amplification: Effects of Pressure Anisotropy PerturbationsJi-Hoon Ha0Korea AeroSpace Administration, Sacheon-si 52535, Republic of KoreaMagnetic field amplification in the early universe is a long-standing problem that has been extensively studied through theoretical and numerical approaches, focusing on turbulent dynamos and the growth of collisionless plasma instabilities. In the post-recombination era, pressure anisotropy drives plasma instabilities, and magnetic field amplification through these instabilities can be faster than that driven by turbulent dynamos. By considering the balance between isotropization through magnetic field amplification and anisotropy generation by external sources such as turbulence and anisotropic cosmic-ray scattering, it is reasonable to assume that the system evolves around an equilibrium anisotropy value. To improve the theoretical modeling of magnetic field amplification in such systems, this study specifically examines pressure anisotropy perturbations near the equilibrium anisotropy value, which may destabilize the system. By analyzing the effects of pressure anisotropy perturbations and their damping rates on the time evolution of cosmic magnetic fields, we highlight the importance of these perturbations in driving plasma instabilities and boosting cosmic magnetic field amplification.https://www.mdpi.com/2218-1997/11/1/9early universeintergalactic mediummagnetic fieldplasma physics |
| spellingShingle | Ji-Hoon Ha A Model for Cosmic Magnetic Field Amplification: Effects of Pressure Anisotropy Perturbations Universe early universe intergalactic medium magnetic field plasma physics |
| title | A Model for Cosmic Magnetic Field Amplification: Effects of Pressure Anisotropy Perturbations |
| title_full | A Model for Cosmic Magnetic Field Amplification: Effects of Pressure Anisotropy Perturbations |
| title_fullStr | A Model for Cosmic Magnetic Field Amplification: Effects of Pressure Anisotropy Perturbations |
| title_full_unstemmed | A Model for Cosmic Magnetic Field Amplification: Effects of Pressure Anisotropy Perturbations |
| title_short | A Model for Cosmic Magnetic Field Amplification: Effects of Pressure Anisotropy Perturbations |
| title_sort | model for cosmic magnetic field amplification effects of pressure anisotropy perturbations |
| topic | early universe intergalactic medium magnetic field plasma physics |
| url | https://www.mdpi.com/2218-1997/11/1/9 |
| work_keys_str_mv | AT jihoonha amodelforcosmicmagneticfieldamplificationeffectsofpressureanisotropyperturbations AT jihoonha modelforcosmicmagneticfieldamplificationeffectsofpressureanisotropyperturbations |