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Updated: Jun 14, 2025
07:17
Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry
Published on: August 1, 2017
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Relaxation to universal non-Maxwellian equilibria in a collisionless plasma
Robert J Ewart1,2, Michael L Nastac1,3, Pablo J Bilbao4
1Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom.
Summary
Turbulent relaxing plasmas reach generic equilibria by maximizing entropy and conserving collisionless invariants. Turbulence drives these invariants to a universal form, creating power-law energy tails in plasmas.
Area of Science:
- Plasma Physics
- Statistical Mechanics
- Turbulence Theory
Background:
- Turbulent plasmas exhibit complex dynamics influenced by conserved quantities.
- Understanding equilibrium states in such systems is crucial for plasma physics.
- Collisionless invariants play a role in plasma memory but are affected by turbulence.
Purpose of the Study:
- To derive generic equilibria for turbulent relaxing plasmas.
- To investigate the influence of short-time collisionless invariants on plasma equilibria.
- To understand how turbulence modifies these invariants and affects the system's long-term behavior.
Main Methods:
- Entropy-maximization procedure applied to turbulent plasmas.
- Accounting for the short-time conservation of collisionless invariants.
- Numerical simulations of beam instabilities in one-dimensional electrostatic plasmas.
Main Results:
- Generic equilibria derived for turbulent relaxing plasmas.
- Collisionless invariants are driven to a universal form by turbulence.
- Numerical confirmation shows a universal power-law tail (exponent -2) in particle energy distribution functions for strong turbulence.
Conclusions:
- Turbulence leads to universal forms of invariants in relaxing plasmas.
- The derived equilibria provide insights into the statistical mechanics of turbulent plasmas.
- Power-law energy tails are a signature of strong turbulence in these systems.
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