Open AccessMach number dependence of the onset of dynamo action
Author(s) -
Haugen Nils Erland L.,
Brandenburg Axel,
Mee Antony J.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.08127.x
Subject(s) - dynamo , physics , magnetic diffusivity , shock (circulatory) , supersonic speed , mach number , magnetic field , turbulence , mechanics , action (physics) , reynolds number , dynamo theory , shock wave , classical mechanics , astrophysics , medicine , quantum mechanics
The effect of compressibility on the onset of non‐helical turbulent dynamo action is investigated using both direct simulations as well as simulations with shock‐capturing viscosities, keeping, however, the regular magnetic diffusivity. It is found that the critical magnetic Reynolds number increases from about 35 in the subsonic regime to about 70 in the supersonic regime. Although the shock structures are sharper in the high‐resolution direct simulations compared with the low‐resolution shock‐capturing simulations, the magnetic field looks roughly similar in both cases and does not show any shock structures. Similarly, the onset of dynamo action is not significantly affected by the shock‐capturing viscosity.