Observation of Kolmogorov Turbulence in the Jovian Magnetosheath From JADE Data

Abstract

The solar wind is the supersonic outward flow of plasma from the Sun. When the turbulent solar wind approaches Jupiter, it crosses a bow shock, which slows the plasma to subsonic speeds and causes significant increase in the plasma's density, temperature, and turbulence level. This region of subsonic plasma between the bow shock and magnetosphere is known as the magnetosheath. Magnetosheath of different sizes with varying properties is seen in the magnetospheres of Earth, Saturn, and Jupiter (Bagenal et al., 2017). The bounding surface of the magnetosphere is called the magnetopause. The magnetopause is the region where the source of the magnetic field changes: inside the magnetopause, the controlling magnetic field is that of Jupiter; while outside, it is the solar wind magnetic field.The magnetosheath is the interface of the solar wind-magnetosphere interaction, affecting the physical processes occurring within Jupiter's magnetopause. The magnetosheath magnetic field and plasma interact at the magnetopause and, consequently, with Jupiter's magnetosphere (Ranquist et al., 2020). Therefore, studying the properties of turbulence in the magnetosheath helps to better understand the dynamical coupling between the solar wind and the magnetosphere and to improve the current models. In addition, the interest in exploring plasma turbulence near Jupiter also lies in its plasma conditions: it has a strong magnetic field, a broad range of plasma β (the ratio of thermal pressure to magnetic pressure) values (Ranquist et al., 2019), and a very large system size, the combination makes the Jovian magnetospheric system a

Beta‐Dependent Constraints on Ion Temperature Anisotropy in Jupiter’s Magnetosheath

“…This can be understood by noting the turbulence correlation scale is close to this time scale. Previous studies reported a correlation time of the turbulent fluctuations to be ∼20 min (Bandyopadhyay et al., 2021). We believe that since the changes in the proton beta are mostly driven by variations in the background density the time scales of variation are set by the turbulence outer scale.…”

“…The Juno observations during a typical magnetosheath crossing are shown in Figure 1. The same magnetosheath interval was studied by Bandyopadhyay et al, 2021 andRanquist et al, 2019. The main plasma parameters, used in this work, are shown.…”

“…Several magnetosheath crossings on the dawn side were obtained from the subsequent orbits. The data collected during these magnetosheath crossings provide a first opportunity to study the statistical properties of waves and instabilities in Jupiter's dawn‐side magnetosheath (Bandyopadhyay et al., 2021; Hospodarsky et al., 2017; Ranquist et al., 2019).…”

Observation of Turbulent Magnetohydrodynamic Cascade in the Jovian Magnetosheath

“…To investigate the compressible MHD turbulence in the Jovian MS, we used Juno's observations analyzed in detail recently by Bandyopadhyay et al (2021). In particular, we consider observations in the dawn side of the Jovian MS obtained by Juno during an MS crossing on 2017 February 20 from 01:00:23 to 23:09:54 UTC.…”

Ion Kinetics of Plasma Flows: Earth's Magnetosheath versus Solar Wind

“…As in the solar wind, magnetosheath pdfs are seen to fall within the anisotropy constraints defined by kinetic instabilities (e.g., Maruca et al 2018, and references therein). Note that although the magnetosheath region is an internal domain of many planetary magnetospheres, properties of magnetic field and plasma fluctuations within magnetosheath are quite different in the Earth, Mercury (Huang et al 2020), Jupiter (Bandyopadhyay et al 2021), andSaturn (Hadid et al 2015) magnetosheaths. For example, for the Earth magnetosheath kinetic Alfvén waves typically provide a dominant contribution to the fluctuations (Alexandrova et al 2004(Alexandrova et al , 2006Chen & Boldyrev 2017;Roberts et al 2018), whereas these waves contribute much less to fluctuations in the Saturn and Mercury magnetosheaths (Hadid et al 2015;Huang et al 2020).…”