Scale dependent alignment between velocity and magnetic field fluctuations in the solar wind and comparisons to Boldyrev's phenomenological theory

TL;DR

This paper investigates the scale-dependent alignment between velocity and magnetic field fluctuations in the solar wind, testing Boldyrev's MHD turbulence theory that predicts a specific power-law relationship.

Contribution

It provides empirical analysis of solar wind data to verify the predicted scale-dependent angle of alignment in MHD turbulence.

Findings

Confirmation of the power-law scaling between angle and scale

Quantitative comparison with Boldyrev's theory

Insights into turbulence dynamics in the solar wind

Abstract

(Abridged abstract) A theory of incompressible MHD turbulence recently developed by Boldyrev predicts the existence of a scale dependent angle of alignment between velocity and magnetic field fluctuations that is proportional to the lengthscale of the fluctuations to the power 1/4. In this study, plasma and magnetic field data from the Wind spacecraft are used to investigate the angle between velocity and magnetic field fluctuations in the solar wind as a function of the timescale of the fluctuations and to look for the power law scaling predicted by Boldyrev.