Dynamical evolution of anisotropies of the solar wind magnetic turbulent outer scale

RUIZ M.E.; DASSO, S.; MATTHAEUS, W.H.; MARSCH, E.; WEYGAND, J. M.

Comparative Magnetic Minima: characterizing quiet times in the Sun and stars

Cambridge University Press

Año: 2012; p. 164 - 167

The evolution of the turbulent properties in the solar wind, during the travel of theparcels of fluid from the Sun to the outer heliosphere still has several unanswered questions. Inthis work, we will present results of an study on the dynamical evolution of turbulent magneticfluctuations in the inner heliosphere. We focused on the anisotropy of the turbulence integralscale, measured parallel and perpendicular to the direction of the local mean magnetic field, andstudy its evolution according to the aging of the plasma parcels observed at different heliodistances.As diagnostic tool we employed single-spacecraft correlation functions computed withobservations collected by Helios 1 & 2 probes over nearly one solar cycle. Our results are consistentwith driving modes with wave-vectors parallel to the direction of the local mean magneticfield near the Sun, and a progressive spectral transfer of energy to modes with perpendicularwave-vectors. Advances made in this direction, as those presented here, will contribute to ourunderstanding of the magnetohydrodynamical turbulence and Alfv´enic-wave activity for thissystem, and will provide a quantitative input for models of charged solar and galactic energeticparticles propagation and diffusion throughout the inner heliosphere.