Sign Singularity of the Local Energy Transfer in Space Plasma Turbulence

Frontiers in Physics

Oreste Pezzi²  Khatuna Chargazia³  Diana Kvaratskhelia⁴  Raffaele Marino⁵  Barbara Giles⁶  Thomas E. Moore⁶  Roy B. Torbert⁷  James L. Burch⁸  Christian L. Vásconez⁹  Giuseppina Nigro^1,10  Silvia Perri^1,10  Federico Fraternale^1,11  Luca Sorriso-Valvo^1,12  Gaetano De Vita^1,12  Alessandro Retinò^1,13  Olivier Le Contel^1,13  Alexandre Gurchumelia^1,14  Oleg Kharshiladze^1,14  Christopher H. K. Chen^1,15  Filomena Catapano^1,16  Emiliya Yordanova^1,17 

[1] 0Gran Sasso Science Institute, L'Aquila, Italy;1INFN/Laboratori Nazionali del Gran Sasso, Assergi, Italy;2I. Vekua Institute of Applied Mathematics, Iv. Javakhishvili Tbilisi State University, Tbilisi, Georgia;3Sokhumi State University, Tbilisi, Georgia;4Laboratoire de Mécanique des Fluides et d'Acoustique, CNRS, École Centrale de Lyon, Université Claude Bernard Lyon, INSA de Lyon, Écully, France;5NASA, Goddard Space Flight Center, Greenbelt, MD, United States;6Space Science Center, University of New Hampshire, Durham, NH, United States;7Southwest Research Institute, San Antonio, TX, United States;Departamento de Física, Escuela Politécnica Nacional, Quito, Ecuador;Dipartimento di Fisica, Università della Calabria, Rende, Italy;Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Turin, Italy;Istituto per la Scienza e Tecnologia dei Plasmi (ISTP), Consiglio Nazionale delle Ricerche, Bari, Italy;LPP-CNRS/Ecole Polytechnique/Sorbonne Université, Paris, France;M. Nodia Institute of Geophysics, Iv. Javakhishvili Tbilisi State University, Tbilisi, Georgia;School of Physics and Astronomy, Queen Mary University of London, London, United Kingdom;Serco Italia for ESA-ESRIN, Frascati, Italy;Swedish Institute of Space Physics, Uppsala, Sweden;

关键词: turbulence;    dissipation;    space plasmas;    magnetosphere;    singularity;   

DOI  :  10.3389/fphy.2019.00108

来源: DOAJ

【 摘 要 】

In weakly collisional space plasmas, the turbulent cascade provides most of the energy that is dissipated at small scales by various kinetic processes. Understanding the characteristics of such dissipative mechanisms requires the accurate knowledge of the fluctuations that make energy available for conversion at small scales, as different dissipation processes are triggered by fluctuations of a different nature. The scaling properties of different energy channels are estimated here using a proxy of the local energy transfer, based on the third-order moment scaling law for magnetohydrodynamic turbulence. In particular, the sign-singularity analysis was used to explore the scaling properties of the alternating positive-negative energy fluxes, thus providing information on the structure and topology of such fluxes for each of the different type of fluctuations. The results show the highly complex geometrical nature of the flux, and that the local contributions associated with energy and cross-helicity non-linear transfer have similar scaling properties. Consequently, the fractal properties of current and vorticity structures are similar to those of the Alfvénic fluctuations.

【 授权许可】

Unknown