Noncanonical Hamiltonian Density Formulation of Hydrodynamics and Ideal Magnetohydrodynamics

1980 ◽  
Vol 45 (10) ◽  
pp. 790-794 ◽  
Author(s):  
Philip J. Morrison ◽  
John M. Greene
Keyword(s):  
Hamiltonian Density ◽  
Ideal Magnetohydrodynamics

The accumulation continua in ideal magnetohydrodynamics

2003 ◽  
Vol 10 (2) ◽  
pp. 413-418 ◽  
Author(s):  
G. O. Spies ◽  
J. A. Tataronis
Keyword(s):  
Ideal Magnetohydrodynamics

scholarly journals Non-ideal magnetohydrodynamics versus turbulence – I. Which is the dominant process in protostellar disc formation?

2020 ◽  
Vol 495 (4) ◽  
pp. 3795-3806 ◽  
Author(s):  
James Wurster ◽  
Benjamin T Lewis
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Rotation Axis ◽  
Low Mass Stars ◽  
Rotation Rates ◽  
Ideal Mhd ◽  
Low Mass ◽  
Dominant Process ◽  
Ideal Magnetohydrodynamics ◽  
Disc Formation

ABSTRACT Non-ideal magnetohydrodynamics (MHD) is the dominant process. We investigate the effect of magnetic fields (ideal and non-ideal) and turbulence (sub- and transsonic) on the formation of circumstellar discs that form nearly simultaneously with the formation of the protostar. This is done by modelling the gravitational collapse of a 1 M⊙ gas cloud that is threaded with a magnetic field and imposed with both rotational and turbulent velocities. We investigate magnetic fields that are parallel/antiparallel and perpendicular to the rotation axis, two rotation rates, and four Mach numbers. Disc formation occurs preferentially in the models that include non-ideal MHD where the magnetic field is antiparallel or perpendicular to the rotation axis. This is independent of the initial rotation rate and level of turbulence, suggesting that subsonic turbulence plays a minimal role in influencing the formation of discs. Aside from first core outflows that are influenced by the initial level of turbulence, non-ideal MHD processes are more important than turbulent processes during the formation of discs around low-mass stars.

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