Modelling general-relativistic plasmas with collisionless moments and dissipative two-fluid magnetohydrodynamics
Abstract
Relativistic plasmas are central to the study of black hole accretion, jet physics, neutron star mergers, and compact object magnetospheres. Despite the need to accurately capture the dynamics of these plasmas and the implications for relativistic transients, their fluid modelling is typically done using a number of (overly) simplifying assumptions, which do not hold in general. This is especially true when the mean free path in the plasma is large compared to the system size, and kinetic effects start to become important. Going beyond common approaches used in the literature, we describe a fully relativistic covariant 14-moment based two-fluid system appropriate for the study of electron–ion or electron–positron plasmas. This generalized Israel-Stewart-like system of equations of motion is obtained directly from the relativistic Boltzmann–Vlasov equation. This new formulation can account for non-ideal effects, such as anisotropic pressures and heat fluxes, not present in previous formulations of two-fluid magnetohydrodynamics. We show that a relativistic two-fluid plasma can be recast as a single fluid coupled to electromagnetic fields with (potentially large) out-of-equilibrium corrections. We keep all electron degrees of freedom, which provide self-consistent evolution equations for electron temperature and momentum. The out-of-equilibrium corrections take the form of a collisional 14-moment closure previously described in the context of viscous single fluids. The equations outlined in this paper are able to capture the full two-fluid character of collisionless plasmas found in black hole accretion and flaring processes around compact objects, as well Braginskii-like two-fluid magnetohydrodynamics applicable to weakly collisional plasmas inside accretion discs.
Additional Information
© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) The authors thank Lev Arzamasskiy, Amitava Bhattacharjee, Gabriel Denicol, Chuanfei Dong, Ammar Hakim, James Juno, Alex Pandya, Frans Pretorius, James Stone, Jason Ten Barge and the members of the CCA-PPPL collaboration for insightful discussions and comments related to this work. ERM gratefully acknowledges support from postdoctoral fellowships at the Princeton Center for Theoretical Science, the Princeton Gravity Initiative, and the Institute for Advanced Study. Research at the Flatiron Institute is supported by the Simons Foundation. JN is partially supported by the U.S. Department of Energy, Office of Science, Office for Nuclear Physics under Award No. DE-SC0021301. DATA AVAILABILITY. No new data was produced in this study.Attached Files
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Additional details
- Alternative title
- Modeling general-relativistic plasmas with collisionless moments and dissipative two-fluid magnetohydrodynamics
- Eprint ID
- 121203
- Resolver ID
- CaltechAUTHORS:20230501-296926000.17
- Institute for Advanced Study
- Simons Foundation
- Princeton University
- DE-SC0021301
- Department of Energy (DOE)
- Created
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2023-05-25Created from EPrint's datestamp field
- Updated
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2023-05-25Created from EPrint's last_modified field