Towards a realistic evaluation of transport coefficients in non-equilibrium space plasmas

Abstract

Recent studies have outlined the interest for the evaluation of transport coefficients in space plasmas, where the observed velocity distributions of plasma particles are conditioned not only by the binary collisions, e.g., at low energies, but also by the energisation of particles from their interaction with wave turbulence and fluctuations, generating the suprathermal Kappa-distributed populations. This paper provides a first estimate of the main transport coefficients based on regularised Kappa distributions (RKDs), which, unlike standard Kappa distributions (SKDs), enable macroscopic parameterisation without mathematical divergences or physical inconsistencies. All transport coefficients derived here, i.e., the diffusion and mobility coefficients, electric conductivity, thermoelectric coefficient and thermal conductivity, are finite and well defined for all values of $\kappa >0$. Moreover, for low values of $\kappa$ (i.e., below the SKD poles), the transport coefficients can be orders of magnitudes higher than the corresponding Maxwellian limits, meaning that significant underestimations can be made if suprathermal electrons are ignored.

arXiv comment13 pages, 5 figures, 1 table

References in corpus (12)

• Kappa distributions: theory and applications in space plasmas
• The multi-scale nature of the solar wind
• The Formation of Kappa-Distribution Accelerated Electron Populations in Solar Flares
• On the interpretation and applicability of $\kappa$-distributions
• Ion Temperatures in the Low Solar Corona: Polar Coronal Holes at Solar Minimum
• A review on solar wind modeling: kinetic and fluid aspects
• Acceleration of weakly collisional solar-type winds
• On the applicability of $\kappa$-distributions
• Temperature anisotropy and differential streaming of solar wind ions -- Correlations with transverse fluctuations
• The diffusion of charged particles in the weakly ionized plasma with power-law kappa-distributions
• The $\kappa$-cookbook: a novel generalizing approach to unify $\kappa$-like distributions for plasma particle modeling
• Transport coefficients of the fully ionized plasma with kappa-distribution and in strong magnetic field

Cited by in corpus (4)

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• Collisional charging of dust particles by suprathermal plasmas. II -- Regularized Kappa distributions
• The Quiet-Sun DEM Under Kappa: Diagnostic Degeneracy and the Failure of the Conductive Closure