Related Experiment Video
Updated: Jul 31, 2025

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic
Published on: August 25, 2016
Radiation Reaction Cooling as a Source of Anisotropic Momentum Distributions with Inverted Populations
1GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal.
Abstract:
Under the presence of strong electromagnetic fields and radiation reaction, plasmas develop anisotropic momentum distributions, characterized by a population inversion. This is a general property of collisionless plasmas when the radiation reaction force is taken into account. We study the case of a plasma in a strong magnetic field and demonstrate the development of ring momentum distributions. The timescales for ring formation are derived for this configuration. The analytical results for the ring properties and the timescales for ring formation are confirmed with particle-in-cell simulations. The resulting momentum distributions are kinetically unstable and are known to lead to coherent radiation emission in astrophysical plasmas and laboratory setups.
Related Concept Videos
Atomic Nuclei: Nuclear Relaxation Processes
Atomic Nuclei: Nuclear Spin State Population Distribution
Momentum And Radiation Pressure
Absorption of Radiation
Radiation Pressure: Problem Solving
The average value of the rate of momentum transfer divided by the absorbing area represents the average force...
Radiation: Applications
The average...

