Charged particle dynamics in the presence of non-Gaussian Lévy electrostatic fluctuations
Artikel i vetenskaplig tidskrift, 2016

Full orbit dynamics of charged particles in a 3-dimensional helical magnetic field in the presence of a-stable Levy electrostatic fluctuations and linear friction modeling collisional Coulomb drag is studied via Monte Carlo numerical simulations. The Levy fluctuations are introduced to model the effect of non-local transport due to fractional diffusion in velocity space resulting from intermittent electrostatic turbulence. The probability distribution functions of energy, particle displacements, and Larmor radii are computed and showed to exhibit a transition from exponential decay, in the case of Gaussian fluctuations, to power law decay in the case of Levy fluctuations. The absolute value of the power law decay exponents is linearly proportional to the Levy index a. The observed anomalous non-Gaussian statistics of the particles’ Larmor radii (resulting from outlier transport events) indicate that, when electrostatic turbulent fluctuations exhibit non-Gaussian Levy statistics, gyro-averaging and guiding centre approximations might face limitations and full particle orbit effects should be taken into account.

Langevin dynamics

Levy fluctuations

Författare

Sara Moradi

Université libre de Bruxelles (ULB)

Diego del-Castillo-Negrete

Oak Ridge National Laboratory

Johan Anderson

Chalmers, Rymd- och geovetenskap, Plasmafysik och fusionsenergi

Physics of Plasmas

1070-664X (ISSN) 1089-7674 (eISSN)

Vol. 23 090704

Ämneskategorier

Fysik

Fusion, plasma och rymdfysik

Styrkeområden

Energi

Fundament

Grundläggande vetenskaper

DOI

10.1063/1.4963394