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July 29, 2015 to August 6, 2015
World Forum
Europe/Amsterdam timezone

RANDOM BALLISTIC INTERPRETATION OF THE NONLINEAR GUIDING CENTER THEORY OF PERPENDICULAR TRANSPORT

Aug 4, 2015, 4:00 PM
1h
Theater Foyer (World Forum)

Theater Foyer

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Board: 38
Poster contribution SH-TH Poster 3 SH

Speaker

David Ruffolo (Mahidol University)

Description

Nonlinear guiding center (NLGC) theory has been used to explain the asymptotic perpendicular diffusion coefficient κ⊥ of energetic charged particles in a turbulent magnetic field, which can be applied to better understand cosmic ray transport. Here we re-derive NLGC, replacing the assumption of diffusive decorrelation with random ballistic decorrelation (RBD), which yields an explicit formula for κ⊥.We note that scattering processes can cause a reversal of the guiding center motion along the field line, i.e., “backtracking,” leading to partial cancellation of contributions to κ⊥, especially for low-wavenumber components of the magnetic turbulence. We therefore include a heuristic backtracking correction (BC) that can be used in combination with RBD. In comparison with computer simulation results for various cases and two different magnetic field models (2D+slab and noisy RMHD), NLGC with RBD and BC provides a substantially improved characterization of the perpendicular diffusion coefficient for a fluctuation amplitude less than or equal to the large-scale magnetic field. Partially supported by the Thailand Research Fund, the Development and Promotion of Science and Technology Talents Project of the Royal Thai Government, the U.S. NSF (AGS-1063439 and SHINE AGS-1156094), NASA (Heliophysics Theory NNX11AJ4G), the Solar Probe Plus/ISIS project, and Thailand’s Ministry of Education.
Registration number following "ICRC2015-I/" 262
Collaboration -- not specified --

Primary author

David Ruffolo (Mahidol University)

Co-authors

Dr Andrew Snodin (King Mongkut's University of Technology North Bangkok) Dr Piyanate Chuychai (Mae Fah Luang University) Mr Taweesak Jitsuk (Mahidol University) Mr Theerasarn Pianpanit (Mahidol University) Prof. William H. Matthaeus (University of Delaware)

Presentation materials

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