Magnetospheric Multiscale Observation of Kinetic Signatures in the Alfvén Vortex

Abstract

Alfvén vortex is a multi-scale nonlinear structure which contributes to intermittency of turbulence. Despite previous explorations mostly on the spatial properties of the Alfvén vortex (i.e., scale, orientation, and motion), the plasma characteristics within the Alfvén vortex are unknown. Moreover, the connection between the plasma energization and the Alfvén vortex still remains unclear. Based on high resolution in-situ measurement from the Magnetospheric Multiscale (MMS) mission, we report for the first time, distinctive plasma features within an Alfvén vortex. This Alfvén vortex is identified to be two-dimensional ($k_{\perp }\gg k_{\Vert }$) quasi-monopole with a radius of ~10 proton gyroscales. Its magnetic fluctuations $\delta B_{\perp }$ are anti correlated with velocity fluctuations $\delta V_{\perp }$, thus the parallel current density $j_{\Vert }$ and flow vorticity ${\omega }_{\Vert }$ are anti-aligned. In different part of the vortex (i.e., edge, middle, center), the ion and electron temperatures are found to be quite different and they behave in the reverse trend: the ion temperature variations are correlated with $j_{\Vert }$, while the electron temperature variations are correlated with ${\omega }_{\Vert }$. Furthermore, the temperature anisotropies, together with the non-Maxwellian kinetic effects, exhibit strong enhancement at peaks of $|{\omega }_{\Vert }|(|j_{\Vert }|)$ within the vortex. Comparison between observations and numerical/theoretical results are made. In addition, the energy-conversion channels and the compressibility associated with the Alfvén vortex are discussed. These results may help to understand the link between coherent vortex structures and the kinetic processes, which determines how turbulence energy dissipate in the weakly-collisional space plasmas.

References in corpus (23)

• Solar Wind Turbulence and the Role of Ion Instabilities
• Recent progress in astrophysical plasma turbulence from solar wind observations
• Energy transfer, pressure tensor and heating of kinetic plasma
• Intermittent Dissipation and Local Heating in the Solar Wind
• Whistler mode waves and the electron heat flux in the solar wind: Cluster observations
• Kinetic dissipation and anisotropic heating in a turbulent collisionless plasma
• Magnetospheric Multiscale Observations of Electron Vortex Magnetic Hole in the Magnetosheath Turbulent Plasma
• Kinetic Signatures and Intermittent Turbulence in the Solar Wind Plasma
• Coherent events and spectral shape at ion kinetic scales in the fast solar wind turbulence
• Electron scale structures and magnetic reconnection signatures in the turbulent magnetosheath
• Compressive Coherent Structures at Ion Scales in the Slow Solar Wind
• Pressure anisotropy and small spatial scales induced by velocity shear
• The Complex Structure of Magnetic Field Discontinuities in the Turbulent Solar Wind
• Vlasov simulations of multi-ion plasma turbulence in the solar wind
• Coherent structures at ion scales in fast solar wind: {\it Cluster} observations
• Differential kinetic dynamics and heating of ions in the turbulent solar wind
• Propinquity of current and vortex structures: effects on collisionless plasma heating
• Coherent structures and spectral energy transfer in turbulent plasma: a space-filter approach
• Proton Heating in Solar Wind Compressible Turbulence with Collisions between Counter-propagating Waves
• Observation of an MHD Alfvén vortex in the slow solar wind
• Occurrence Rates and Heating Effects of Tangential and Rotational Discontinuities as Obtained from Three-dimensional Simulation of Magnetohydrodynamic Turbulence
• Drift-Alfven vortex structures in the edge region of a fusion relevant plasma
• Fluid theory of coherent magnetic vortices in high-beta space plasmas

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• Observational quantification of three-dimensional anisotropies and scalings of space plasma turbulence at kinetic scales
• Contribution of Magnetic Reconnection Events to Energy Dissipation in Magnetosheath Turbulence
• Observational evidence for solar wind proton heating by ion-scale turbulence
• Magnetic helicity signature and its role in regulating magnetic energy spectra and proton temperatures in the solar wind
• Dependence of ion temperatures on alpha-proton differential flow vector and heating mechanisms in the solar wind
• Space-filter techniques for quasi-neutral hybrid-kinetic models
• Inverse cascade and magnetic vortices in kinetic Alfvén-wave turbulence
• Kinetic features for the identification of Kelvin-Helmholtz vortices in \textit{in situ} observations
• Power Anisotropy, Dispersion Signature and Turbulence Diffusion Region in the 3D Wavenumber Domain of Space Plasma Turbulence
• Ion-Scale Solitary Structures in the Solar Wind Observed by Solar Orbiter and Parker Solar Probe