Topology of Magnetic and Velocity Fields at Kinetic Scales in Incompressible Plasma Turbulence

Abstract

The topology of the magnetic and velocity fields at the kinetic scales are investigated in the context of nearly incompressible magnetosheath plasma turbulence. Using the unprecedented high‐resolution data from the Magnetospheric MultiScale mission, the joint probability distribution functions of geometrical invariants characterizing the magnetic and velocity fields gradient tensor at the kinetic scales are computed. The topological features of the magnetic and velocity field gradient tensors and their symmetric component tensors present axisymmetric distribution patterns, indicating that the structure of the plasma turbulence at the kinetic scales are different from those in hydrodynamic and magnetohydrodynamic turbulence. Moreover, a strong correlation between the straining and rotational parts of the magnetic and velocity field gradient tensors was found, which manifests the dominance of sheet‐like structures at the kinetic‐scales dissipation in incompressible plasma turbulence.

Kinetic-scale Topological Structures Associated with Energy Dissipation in the Turbulent Reconnection Outflow

“…Summing the counts above and below this line indicates that the ratio between O-type topologies (D X > 0) and X-type topologies (D X < 0) is 66.16%:33.84%. This dominant distribution of O-type topologies is consistent with the results observed in the solar wind (e.g., Quattrociocchi et al 2019;Hnat et al 2021) and the Earthʼs magnetosheath (e.g., Ji et al 2023;Zhang et al 2023). c) and (d)), the correlations seem to be weaker, which are analogous to the results observed at Earthʼs magnetosheath (e.g., Bandyopadhyay et al 2020;Zhang et al 2023), and the two correlation coefficients are 0.58 and 0.82, respectively.…”

“…Recently, a methodology constructed by vector-field gradient tensor could reveal structures and dynamics in turbulence using a series of geometrical invariants (e.g., Chong et al 1990;Martín et al 1998;Meneveau 2011). It has been applied in local streamline-topology classification in both magnetohydrodynamic (MHD) turbulence simulations (e.g., Dallas & Alexakis 2013) and in situ observations in the turbulent solar wind (e.g., Quattrociocchi et al 2019;Hnat et al 2021), turbulent Earthʼs magnetosheath (e.g., Consolini et al 2015;Ji et al 2023;Zhang et al 2023), and the magnetic reconnection region (e.g., Consolini et al 2018). In order to advance the understanding of turbulent reconnection outflows in the terrestrial magnetotail, the aim of this study is to apply the topology-classification methodology to in situ observations from the Magnetospheric Multiscale (MMS) mission and reveal the most relevant local field topology associated with energy dissipation.…”

Guide Field Dependence of Energy Conversion and Magnetic Topologies in Reconnection Turbulent Outflow

“…Topologies of magnetic structures that are accompanied by energy conversion can be categorized through the geometrical invariants (e.g., Huang et al., 2023; Quattrociocchi et al., 2019; Zhang et al., 2023). Considering the spatial variation of the magnetic field, the gradient tensor X = ∇ B ( B is the magnetic field vector) can be built to refer to the localized features.…”

Statistical Characteristics of Electron Vortexes in the Terrestrial Magnetosheath

“…Turbulence is a universal phenomenon in the plasma environment, which widely exists in various space and astrophysical plasmas, including solar wind, planetary magnetosphere, interstellar medium, etc. (Tu & Marsch 1995;Zhou et al 2004;Sahraoui et al 2009Sahraoui et al , 2010Sahraoui et al , 2013Sahraoui et al , 2020Bruno & Carbone 2013;Falceta-Gonçalves et al 2014;Huang et al 2020;Zhang et al 2022Zhang et al , 2023. The magnetosheath is also occupied by a high level of magnetic field and plasma fluctuations, providing an ideal laboratory for studying plasma turbulence (Sahraoui et al 2004(Sahraoui et al , 2006(Sahraoui et al , 2020Huang et al 2017a;Huang 2022).…”