nouveau bandeau du PNST 2022

Nature of Solar Wind Turbulence at Electron Scale
Vincent David  1@  , Sébastien Galtier  1  , Romain Meyrand  2  
1 : Laboratoire de Physique des Plasmas
Observatoire de Paris, Ecole Polytechnique, Sorbonne Université, Université Paris-Saclay, Centre National de la Recherche Scientifique
2 : University of Otago [Dunedin, Nouvelle-Zélande]

Solar wind turbulence at electron scale is generally thought to be governed primarily by kinetic Alfvén waves (KAW), but the monofractal behavior observed is a puzzling problem that contradicts the standard properties of intermittency. In this Letter, we investigate this long-standing problem using direct numerical simulations (DNS) of three-dimensional electron reduced magnetohydrodynamics (ERMHD). Both weak and strong KAW turbulence regimes are studied in the balanced case. After recovering the expected theoretical predictions for the magnetic spectra, a higher-order multiscale statistical analysis is performed. This study reveals a striking difference between the two regimes, with the emergence of monofractality only in weak turbulence, whereas strong turbulence is multifractal. This result, combined with recent studies, shows the relevance of collisionless weak KAW turbulence to describe the solar wind at electron scale. 


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