Dissipation triggers dynamical two-stream instability
Dissipation triggers dynamical two-stream instability
Two coupled, interpenetrating fluids suffer instabilities beyond certain critical counterflows. For ideal fluids, an energetic instability occurs at the point where a sound mode inverts its direction due to the counterflow, while dynamical instabilities only occur at larger relative velocities. Here we discuss two relativistic fluids, one of which is dissipative. Using linearized hydrodynamics, we show that in this case the energetic instability turns dynamical, i.e., there is an exponentially growing mode, and this exponential growth only occurs in the presence of dissipation. This result is general and does not rely on an underlying microscopic theory. It can be applied to various two-fluid systems for instance in the interior of neutron stars. We also point out that under certain circumstances the two-fluid system exhibits a mode analogous to the r-mode in neutron stars that can become unstable for arbitrarily small values of the counterflow.
gr-qc, astro-ph.HE, hep-ph, physics.plasm-ph
https://www.mdpi.com/2571-712X/2/4/28
457-480
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Schmitt, Andreas
1765159f-255f-45e7-94ea-58c1c883d65f
31 October 2019
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Schmitt, Andreas
1765159f-255f-45e7-94ea-58c1c883d65f
Andersson, Nils and Schmitt, Andreas
(2019)
Dissipation triggers dynamical two-stream instability.
Particles, 2 (4), .
(https://www.mdpi.com/2571-712X/2/4/28).
Abstract
Two coupled, interpenetrating fluids suffer instabilities beyond certain critical counterflows. For ideal fluids, an energetic instability occurs at the point where a sound mode inverts its direction due to the counterflow, while dynamical instabilities only occur at larger relative velocities. Here we discuss two relativistic fluids, one of which is dissipative. Using linearized hydrodynamics, we show that in this case the energetic instability turns dynamical, i.e., there is an exponentially growing mode, and this exponential growth only occurs in the presence of dissipation. This result is general and does not rely on an underlying microscopic theory. It can be applied to various two-fluid systems for instance in the interior of neutron stars. We also point out that under certain circumstances the two-fluid system exhibits a mode analogous to the r-mode in neutron stars that can become unstable for arbitrarily small values of the counterflow.
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More information
Accepted/In Press date: 18 October 2019
Published date: 31 October 2019
Additional Information:
20 pages, 4 figures, v2: minor changes in the text, references added, version accepted for publication
Keywords:
gr-qc, astro-ph.HE, hep-ph, physics.plasm-ph
Identifiers
Local EPrints ID: 440750
URI: http://eprints.soton.ac.uk/id/eprint/440750
DOI: https://www.mdpi.com/2571-712X/2/4/28
PURE UUID: 94a5071d-4a3f-45d5-9b2e-d52dc21f408e
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Date deposited: 14 May 2020 16:49
Last modified: 17 Mar 2024 03:40
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