Self-consistent Castaing distribution of solar wind turbulent fluctuations

TL;DR

This paper introduces a self-consistent, parameter-free Castaing model to describe the intermittency of solar wind turbulence, validated against spacecraft data, supporting the multifractal energy cascade theory.

Contribution

The paper develops and tests a new self-consistent, parameter-free Castaing model for solar wind turbulence, improving understanding of intermittency and multifractal energy cascades.

Findings

Good agreement between model and experimental PDFs

Supports multifractal energy cascade hypothesis

Applicable to different solar wind regimes

Abstract

The intermittent behavior of solar wind turbulent fluctuations has often been investigated through the modeling of their probability distribution functions (PDFs). Among others, the Castaing model (Castaing et al. 1990) has successfully been used in the past. In this paper, the energy dissipation field of solar wind turbulence has been studied for fast, slow and polar wind samples recorded by Helios 2 and Ulysses spacecraft. The statistical description of the dissipation rate has then be used to remove intermittency through conditioning of the PDFs. Based on such observation, a self-consistent, parameter-free Castaing model is presented. The self-consistent model is tested against experimental PDFs, showing good agreement and supporting the picture of a multifractal energy cascade at the origin of solar wind intermittency.