Original Research ARTICLE
Sign singularity of the local energy transfer in space plasma turbulence
- 1Escuela Politécnica Nacional, Ecuador
- 2Institute of Nanotechnology (NANOTEC), Italy
- 3Department of Applied Science and Technology, Polytechnic University of Turin, Italy
- 4Tbilisi State University, Georgia
- 5Department of Physics, University of Calabria, Italy
- 6Other, Italy
- 7UMR7648 Laboratoire de physique des plasmas (LPP), France
- 8School of Physics and Astronomy, Faculty of Science and Engineering, Queen Mary University of London, United Kingdom
- 9Institute for Space Physics (Uppsala), Sweden
- 10Gran Sasso Science Institute, Italy
- 11Gran Sasso National Laboratory (INFN), Italy
- 12Ilia Vekua Institute of Applied Mathematics, Tbilisi State University, Georgia
- 13Sokhumi State University, Georgia
- 14Goddard Space Flight Center, United States
- 15Space Science Center, University of New Hampshire, United States
- 16Southwest Research Institute, United States
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 nonlinear transfer have similar scaling properties. Consequently, the fractal properties of current and vorticity structures are similar to those of the Alfv\'enic fluctuations.
Keywords: Turbulence, dissipation, Space plasmas, magnetosphere, singularity
Received: 30 May 2019;
Accepted: 11 Jul 2019.
Edited by:Alexandros Chasapis, University of Delaware, United States
Reviewed by:Annick Pouquet, Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, United States
Wieslaw M. Macek, Space Research Center (PAN), Poland
Copyright: © 2019 Sorriso-Valvo, De Vita, Fraternale, Gurchumelia, Perri, Nigro, Catapano, Retinò, Chen, Yordanova, Pezzi, Chargazia, Kharshiladze, Kvaracxelia, Vasconez, Le Contel, Giles, Moore, Torbert and Burch. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Luca Sorriso-Valvo, Escuela Politécnica Nacional, Quito, 170150, Pichincha, Ecuador, email@example.com