Structure of Stationary Strong Imbalanced Turbulence

TL;DR

This study uses high-resolution simulations to analyze the spectrum and structure of stationary strong imbalanced MHD turbulence, revealing differences in Alfvenic components and challenging existing models.

Contribution

It provides new insights into the structure of imbalanced turbulence and tests the validity of existing models using detailed numerical simulations.

Findings

Driven imbalanced turbulence maintains a stationary state at high imbalance.

The dominant and subdominant Alfvenic components exhibit notably different structures.

Several existing models of strong imbalanced turbulence are inconsistent with observed energy ratios.

Abstract

In this paper we systematically study the spectrum and structure of incompressible MHD turbulence by means of high resolution direct numerical simulations. We considered both balanced and imbalanced (cross-helical) cases and simulated sub-Alfvenic as well as trans-Alfvenic turbulence. This paper extends numerics preliminarily reported in Beresnyak & Lazarian (2008). We confirm that driven imbalanced turbulence has a stationary state even for high degrees of imbalance. Our major finding is that the structure of the dominant and subdominant Alfvenic components are notably different. Using the most robust observed quantities, such as the energy ratio, we were able to reject several existing models of strong imbalanced turbulence.