Artículos de revistas
Test Particle Energization and the Anisotropic Effects of Dynamical MHD Turbulence
Fecha
2017-11Registro en:
González, C. A.; Dmitruk, Pablo Ariel; Mininni, Pablo Daniel; Matthaeus, W.H.; Test Particle Energization and the Anisotropic Effects of Dynamical MHD Turbulence; IOP Publishing; Astrophysical Journal; 850; 1; 11-2017; 1-12
0004-637X
CONICET Digital
CONICET
Autor
González, C. A.
Dmitruk, Pablo Ariel
Mininni, Pablo Daniel
Matthaeus, W.H.
Resumen
In this paper, we analyze the effect of dynamical three-dimensional magnetohydrodynamic (MHD) turbulence on test particle acceleration and compare how this evolving system affects particle energization by current sheet interaction, as opposed to frozen-in-time fields. To do this, we analyze the ensemble particle acceleration for static electromagnetic fields extracted from direct numerical simulations of the MHD equations, and compare it with the dynamical fields. We show that a reduction in particle acceleration in the dynamical model results from particle trapping in field lines, which forces the particles to be advected by the flow and suppresses long exposures to the strong electric field gradients that take place between structures and generate (among other effects) an efficient particle acceleration in the static case. In addition, we analyze the effect of anisotropy caused by the mean magnetic field. It is well known that for sufficiently strong external fields, the system experiences a transition toward a two-dimensional flow. This causes an increment in the size of the coherent structures, resulting in a magnetized state of the particles and a reduction in particle energization.