Higher-order nonequilibrium term: Effective power density quantifying evolution towards or away from local thermodynamic equilibrium
arXiv:2402.12477 · doi:10.1103/PhysRevE.109.015205
Abstract
A common approach to assess the nature of energy conversion in a classical fluid or plasma is to compare power densities of the various possible energy conversion mechanisms. A forefront research area is quantifying energy conversion for systems that are not in local thermodynamic equilibrium (LTE), as is common in a number of fluid and plasma systems. Here, we introduce the ``higher-order non-equilibrium term'' (HORNET) effective power density that quantifies the rate of change of departure of a phase space density from LTE. It has dimensions of power density, which allows for quantitative comparisons with standard power densities. We employ particle-in-cell simulations to calculate HORNET during two processes, namely magnetic reconnection and decaying kinetic turbulence in collisionless magnetized plasmas, that inherently produce non-LTE effects. We investigate the spatial variation of HORNET and the time evolution of its spatial average. By comparing HORNET with power densities describing changes to the internal energy (pressure dilatation, , and divergence of the vector heat flux density), we find that HORNET can be a significant fraction of these other measures (8\% and 35\% for electrons and ions, respectively, for reconnection; up to 67\% for both electrons and ions for turbulence), meaning evolution of the system towards or away from LTE can be dynamically important. Applications to numerous plasma phenomena are discussed.
arXiv comment19 pages (including references), 7 figures
References in corpus (30)
- Astrophysical gyrokinetics: kinetic and fluid turbulent cascades in magnetized weakly collisional plasmas
- Astrophysical Gyrokinetics: Basic Equations and Linear Theory
- The microphysics of collisionless shock waves
- Evidence for Electron Landau Damping in Space Plasma Turbulence
- Energy transfer, pressure tensor and heating of kinetic plasma
- Transition from ion-coupled to electron-only reconnection: Basic physics and implications for plasma turbulence
- Measuring Collisionless Damping in Heliospheric Plasmas using Field-Particle Correlations
- Pressure anisotropy and small spatial scales induced by velocity shear
- Diagnosing collisionless energy transfer using field-particle correlations: gyrokinetic turbulence
- Dependence of Kinetic Plasma Turbulence on Plasma beta
- Scale dependence of energy transfer in turbulent plasma
- Pressure-Strain Interaction as the Energy Dissipation Estimate in Collisionless Plasma
- A Prospectus on Kinetic Heliophysics
- Dissipation measures in weakly-collisional plasmas
- Diagnosing collisionless energy transfer using field-particle correlations: Alfven-Ion Cyclotron Turbulence
- Exploring the Statistics of Magnetic Reconnection X-points in Kinetic Particle-in-Cell (PIC) Turbulence
- Relativistic Magnetic Reconnection in the Laboratory
- Energy Dissipation and Entropy in Collisionless Plasma
- Pressure-Strain Interaction: I. On Compression, Deformation, and Implications For Pi-D
- Energy conversion in turbulent weakly-collisional plasmas: Eulerian Hybrid Vlasov-Maxwell simulations
- Decomposition of Plasma Kinetic Entropy into Position and Velocity Space and the Use of Kinetic Entropy in Particle-in-Cell Simulations
- Electron acceleration and thermalization at magnetotail separatrices
- Quantifying Energy Conversion in Higher Order Phase Space Density Moments in Plasmas
- Pressure-Strain Interaction: III. Particle-in-Cell Simulations of Magnetic Reconnection
- A Field-Particle Correlation Analysis of a Perpendicular Magnetized Collisionless Shock
- Kinetic Entropy-Based Measures of Distribution Function Non-Maxwellianity: Theory and Simulations
- Pressure-Strain Interaction: II. Decomposition in Magnetic Field-Aligned Coordinates
- The Force Balance of Electrons During Kinetic Anti-parallel Magnetic Reconnection
- Energy transport during 3D small-scale reconnection driven by anisotropic plasma turbulence
- Energy Repartition and Entropy Generation across the Earth's Bow Shock: MMS Observations