Intermittent turbulence, noisy fluctuations and wavy structures in the Venusian magnetosheath and wake

TL;DR

This study analyzes magnetic fluctuations in Venus's magnetosheath and wake, revealing diverse turbulence types and scaling behaviors linked to solar wind interactions, with implications for plasma heating.

Contribution

It provides a comprehensive statistical analysis of magnetic fluctuations in Venus's space environment, identifying different spectral scaling features and their physical origins.

Findings

Noisy fluctuations in magnetosheath and wake

Multi-scale turbulence at boundary layers and shocks

Non-Gaussian intermittency in turbulence statistics

Abstract

Recent research has shown that distinct physical regions in the Venusian induced magnetosphere are recognizable from the variations of strength of the magnetic field and its wave/fluctuation activity. In this paper the statistical properties of magnetic fluctuations are investigated in the Venusian magnetosheath and wake regions. The main goal is to identify the characteristic scaling features of fluctuations along Venus Express (VEX) trajectory and to understand the specific circumstances of the occurrence of different types of scalings. For the latter task we also use the results of measurements from the previous missions to Venus. Our main result is that the changing character of physical interactions between the solar wind and the planetary obstacle is leading to different types of spectral scaling in the near-Venusian space. Noisy fluctuations are observed in the magnetosheath, wavy structures near the terminator and in the nightside near-planet wake. Multi-scale turbulence is observed at the magnetosheath boundary layer and near the quasi-parallel bow shock. Magnetosheath boundary layer turbulence is associated with an average magnetic field which is nearly aligned with the Sun-Venus line. Noisy magnetic fluctuations are well described with the Gaussian statistics. Both magnetosheath boundary layer and near shock turbulence statistics exhibit non-Gaussian features and intermittency over small spatio-temporal scales. The occurrence of turbulence near magnetosheath boundaries can be responsible for the local heating of plasma observed by previous missions.