Open AccessInverse transfer of magnetic helicity in supersonic magnetohydrodynamic turbulence
Author(s) -
JeanMathieu Teissier,
WolfChristian Müller
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1623/1/012011
Subject(s) - physics , helicity , magnetic helicity , magnetohydrodynamics , mach number , magnetic field , magnetic energy , supersonic speed , mechanics , turbulence , classical mechanics , magnetohydrodynamic turbulence , quantum mechanics , magnetization
The inverse transfer of magnetic helicity is studied through a fourth-order finite volume numerical scheme in the framework of compressible ideal magnetohydrodynamics (MHD), with an isothermal equation of state. Using either a purely solenoidal or purely compressive mechanical driving, a hydrodynamic turbulent steady-state is reached, to which small-scale magnetic helical fluctuations are injected. The steady-state root mean squared Mach numbers considered range from 0.1 to about 11. In all cases, a growth of magnetic structures is observed. While the measured magnetic helicity spectral scaling exponents are similar to the one measured in the incompressible case for the solenoidally-driven runs, significant deviations are observed even at relatively low Mach numbers when using a compressive driving. A tendency towards equipartition between the magnetic and kinetic fields in terms of energy and helicity is noted. The joint use of the helical decomposition in the framework of shell-to-shell transfer analysis reveals the presence of three distinct features in the global picture of a magnetic helicity inverse transfer. Those are individually associated with specific scale ranges of the advecting velocity field and commensurate helical contributions.