Suppression of inverse magnetic energy transfer in collisionless marginally magnetized plasmas
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2025
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866909820723920896 |
|---|---|
| author | Liu, Zhuo Zhou, Muni Loureiro, Nuno F. G. |
| author_facet | Liu, Zhuo Zhou, Muni Loureiro, Nuno F. G. |
| contents | We investigate the inverse cascade of magnetic energy in decaying, collisionless plasmas with moderate to high-$β$ values via first-principles numerical simulations and analytical theory. We find that pressure-anisotropy-driven instabilities, in particular the firehose instability, suppress reconnection-driven coalescence of magnetic structures (i.e., inverse transfer) by nullifying magnetic tension. This suppression leaves such structures elongated and confined to scales comparable to the Larmor radius of the particles. The presence of a magnetic guide field of sufficient strength, or a greater scale separation between the initial size of the magnetic structures and the Larmor radius, restores the system's ability to inverse transfer magnetic energy. These results reveal that inverse energy transfer in collisionless plasmas is not guaranteed, but instead sensitively depends on magnetization. In the astrophysical context, this identifies a kinetic mechanism by which Weibel-generated seed fields may fail to merge consistently, potentially limiting their role in cosmic magnetogenesis. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_01573 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Suppression of inverse magnetic energy transfer in collisionless marginally magnetized plasmas Liu, Zhuo Zhou, Muni Loureiro, Nuno F. G. Plasma Physics High Energy Astrophysical Phenomena We investigate the inverse cascade of magnetic energy in decaying, collisionless plasmas with moderate to high-$β$ values via first-principles numerical simulations and analytical theory. We find that pressure-anisotropy-driven instabilities, in particular the firehose instability, suppress reconnection-driven coalescence of magnetic structures (i.e., inverse transfer) by nullifying magnetic tension. This suppression leaves such structures elongated and confined to scales comparable to the Larmor radius of the particles. The presence of a magnetic guide field of sufficient strength, or a greater scale separation between the initial size of the magnetic structures and the Larmor radius, restores the system's ability to inverse transfer magnetic energy. These results reveal that inverse energy transfer in collisionless plasmas is not guaranteed, but instead sensitively depends on magnetization. In the astrophysical context, this identifies a kinetic mechanism by which Weibel-generated seed fields may fail to merge consistently, potentially limiting their role in cosmic magnetogenesis. |
| title | Suppression of inverse magnetic energy transfer in collisionless marginally magnetized plasmas |
| topic | Plasma Physics High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2510.01573 |