Suppression of Inverse Magnetic Energy Transfer in Collisionless Marginally Magnetized Plasmas
Year: 2025
Type: article
Abstract: We investigate the inverse cascade of magnetic energy in decaying, collisionless pair 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. The presence of a magnetic guide field of sufficient strength restores the system’s ability to inverse transfer magnetic energy. These results reveal that inverse energy transfer in collisionless plasmas is not guaranteed, but rather depends sensitively 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.
Authors: Zhuo Liu, Muni Zhou, Nuno F. Loureiro
Institutions: Massachusetts Institute of Technology, Dartmouth College
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Funders: U.S. Department of Energy, MathWorks
OpenAlex ID: W7114811032