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Title: Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence

Abstract

Estimation of the energy cascade rate in the inertial range of solar wind turbulence has been done so far mostly within incompressible magnetohydrodynamics (MHD) theory. Here, we go beyond that approximation to include plasma compressibility using a reduced form of a recently derived exact law for compressible, isothermal MHD turbulence. Using in situ data from the THEMIS / ARTEMIS spacecraft in the fast and slow solar wind, we investigate in detail the role of the compressible fluctuations in modifying the energy cascade rate with respect to the prediction of the incompressible MHD model. In particular, we found that the energy cascade rate (1) is amplified particularly in the slow solar wind; (2) exhibits weaker fluctuations in spatial scales, which leads to a broader inertial range than the previous reported ones; (3) has a power-law scaling with the turbulent Mach number; (4) has a lower level of spatial anisotropy. Other features of solar wind turbulence are discussed along with their comparison with previous studies that used incompressible or heuristic (nonexact) compressible MHD models.

Authors:
; ;  [1]
  1. LPP, CNRS, Ecole Polytechnique, UPMC Univ Paris 06, Univ. Paris-Sud, Observatoire de Paris, Université Paris-Saclay, Sorbonne Universités, PSL Research University, F-91128 Palaiseau (France)
Publication Date:
OSTI Identifier:
22661260
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 838; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; APPROXIMATIONS; COMPARATIVE EVALUATIONS; COMPRESSIBILITY; FLUCTUATIONS; FORECASTING; MACH NUMBER; MAGNETOHYDRODYNAMICS; PLASMA; SOLAR WIND; SPACE VEHICLES; TURBULENCE; WASTE HEAT UTILIZATION

Citation Formats

Hadid, L. Z., Sahraoui, F., and Galtier, S., E-mail: lina.hadid@lpp.polytechnique.fr. Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA603F.
Hadid, L. Z., Sahraoui, F., & Galtier, S., E-mail: lina.hadid@lpp.polytechnique.fr. Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence. United States. doi:10.3847/1538-4357/AA603F.
Hadid, L. Z., Sahraoui, F., and Galtier, S., E-mail: lina.hadid@lpp.polytechnique.fr. Mon . "Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence". United States. doi:10.3847/1538-4357/AA603F.
@article{osti_22661260,
title = {Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence},
author = {Hadid, L. Z. and Sahraoui, F. and Galtier, S., E-mail: lina.hadid@lpp.polytechnique.fr},
abstractNote = {Estimation of the energy cascade rate in the inertial range of solar wind turbulence has been done so far mostly within incompressible magnetohydrodynamics (MHD) theory. Here, we go beyond that approximation to include plasma compressibility using a reduced form of a recently derived exact law for compressible, isothermal MHD turbulence. Using in situ data from the THEMIS / ARTEMIS spacecraft in the fast and slow solar wind, we investigate in detail the role of the compressible fluctuations in modifying the energy cascade rate with respect to the prediction of the incompressible MHD model. In particular, we found that the energy cascade rate (1) is amplified particularly in the slow solar wind; (2) exhibits weaker fluctuations in spatial scales, which leads to a broader inertial range than the previous reported ones; (3) has a power-law scaling with the turbulent Mach number; (4) has a lower level of spatial anisotropy. Other features of solar wind turbulence are discussed along with their comparison with previous studies that used incompressible or heuristic (nonexact) compressible MHD models.},
doi = {10.3847/1538-4357/AA603F},
journal = {Astrophysical Journal},
number = 1,
volume = 838,
place = {United States},
year = {Mon Mar 20 00:00:00 EDT 2017},
month = {Mon Mar 20 00:00:00 EDT 2017}
}
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