Regularized κ-distributions with non-diverging moments

¹ Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum D-44780 Bochum, Germany
² Research Department, Plasmas with Complex Interactions, Ruhr-Universität Bochum - 44780 Bochum, Germany
³ Centre for Mathematical Plasma Astrophysics, KU Leuven - Celestijnenlaan 200B, B-3001 Leuven Belgium

^(a) kls@tp4.rub.de

Received: 18 December 2017
Accepted: 31 January 2018

Abstract

For various plasma applications the so-called (non-relativistic) κ-distribution is widely used to reproduce and interpret the suprathermal particle populations exhibiting a power-law distribution in velocity or energy. Despite its reputation the standard κ-distribution as a concept is still disputable, mainly due to the velocity moments M_l which make a macroscopic characterization possible, but whose existence is restricted only to low orders . In fact, the definition of the κ-distribution itself is conditioned by the existence of the moment of order l = 2 (i.e., kinetic temperature) satisfied only for . In order to resolve these critical limitations we introduce the regularized κ-distribution with non-diverging moments. For the evaluation of all velocity moments a general analytical expression is provided enabling a significant step towards a macroscopic (fluid-like) description of space plasmas, and, in general, any system of κ-distributed particles.