General-relativistic and non-ideal radiative cooling in neutron star magnetospheres
arXiv:2603.25949 · doi:10.1093/mnras/stag1178
Abstract
Radiation reaction cooling plays an important role in describing the extreme plasma conditions found in the magnetospheres of astrophysical compact objects. Strong electromagnetic fields, characteristic of these environments, can trigger the development of anisotropic ring-shaped plasma distributions with inverted Landau populations in momentum space. In this work, we present the first systematic investigation of this mechanism in realistic astrophysical configurations, by accounting for how non-uniform electromagnetic field geometries and general-relativistic effects modify the phase-space dynamics of radiatively cooled plasmas. We demonstrate analytically that drift velocities favour the formation of spiral-shaped momentum distributions that still display inverted Landau populations, and estimate the minimum and maximum plasma injection distances required for inverted momentum distributions to be able to power the emission of coherent radiation through kinetic instabilities. From numerical simulations, we conclude that curved spacetime increases the gradient of the distribution function responsible for the development of kinetic instabilities, and prolongs the persistence of the inverted momentum structure relative to flat spacetime, confirming that realistic astrophysical conditions preserve and enhance the conditions necessary for synchrotron-powered emission of coherent radiation to occur.
12 pages, 5 figures
References in corpus (26)
- A bright millisecond radio burst of extragalactic origin
- Fast Radio Bursts
- Fast radio bursts as synchrotron maser emission from decelerating relativistic blast waves
- Radiation Reaction Effects on Radiation Pressure Acceleration
- Coherent Emission Mechanisms in Astrophysical Plasmas
- Time-dependent pair cascades in magnetospheres of neutron stars I. Dynamics of the polar cap cascade with no particle supply from the neutron star surface
- Ab-initio pulsar magnetosphere: three-dimensional particle-in-cell simulations of oblique pulsars
- The synchrotron maser emission from relativistic shocks in Fast Radio Bursts: 1D PIC simulations of cold pair plasmas
- Electrodynamics of pulsar magnetospheres
- A radio pulsar phase from SGR J1935+2154 provides clues to the magnetar FRB mechanism
- The discovery and scientific potential of fast radio bursts
- An introduction to the relativistic kinetic theory on curved spacetimes
- The Linear Instability of Dilute Ultrarelativistic Pair Beams
- Reconnection-driven flares in 3D black hole magnetospheres -- A scenario for hot spots around Sagittarius A*
- Radio Emission and Electric Gaps in Pulsar Magnetospheres
- Radiation reaction cooling as a source of anisotropic momentum distributions with inverted populations
- Synchrotron Firehose Instability
- Scaling up global kinetic models of pulsar magnetospheres using a hybrid force-free-PIC numerical approach
- Pulsar Magnetosphere : A General Relativistic Treatment
- Ring momentum distributions as a general feature of Vlasov dynamics in the synchrotron dominated regime
- OSIRIS-GR: General relativistic activation of the polar cap of a compact neutron star
- Radiation reaction effects in relativistic plasmas -- the electrostatic limit
- Brightness temperature constraints on coherent processes in magnetospheres of neutron stars
- Magnetic frame-dragging correction to the electromagnetic solution of a compact neutron star
- Radiative cooling induced coherent maser emission in relativistic plasmas
- General-relativistic and non-ideal radiative cooling in neutron star magnetospheres