Spacetime Hall-MHD Turbulence at Sub-ion Scales: Structures or Waves?
| Autor: | Petr Hellinger, Mirko Piersanti, Emanuele Papini, Andrea Verdini, Luca Franci, Antonio Cicone, Simone Landi |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Whistler Magnetic energy Turbulence FOS: Physical sciences Spectral density Astronomy and Astrophysics Plasma Polarization (waves) Kinetic energy 01 natural sciences Physics - Plasma Physics Space Physics (physics.space-ph) Space plasmas Solar wind Interplanetary turbulence Plasma astrophysics Computational physics Plasma Physics (physics.plasm-ph) Physics - Space Physics Physics::Plasma Physics Space and Planetary Science Beta (plasma physics) Physics::Space Physics 0103 physical sciences 010303 astronomy & astrophysics 0105 earth and related environmental sciences |
| Popis: | Spatiotemporal properties of two-dimensional (2D) Hall-magnetohydrodynamic turbulence at intermediate plasma $\beta=2$ are studied by means of Fast Iterative Filtering, a new technique for the decomposition of nonstationary nonlinear signals. Results show that the magnetic energy at sub-ion scales is concentrated in perturbations with frequencies smaller than the ion-cyclotron (IC) frequency and with polarization properties that are incompatible with both kinetic Alfv\'en waves (KAWs) and IC waves. At higher frequencies, we clearly identify signatures of both whistler waves and KAWs, however their energetic contribution to the magnetic power spectrum is negligible. We conclude that the dynamics of 2D Hall-MHD turbulence at sub-ion scales is mainly driven by localized intermittent structures, with no significant contribution of wavelike fluctuations. Comment: 10 pages, 5 figures. Accepted for publication on The Astrophysical Journal Letters |
| Databáze: | OpenAIRE |
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