On the role and value of β in incompressible MHD simulations

Robert Chahine (1) , Wouter J.T. Bos (1)

1 LMFA - Laboratoire de Mecanique des Fluides et d'Acoustique

The parameter β, defined as the ratio of the pressure to the square of the magnetic field, is widely used to characterize astrophysical and fusion plasmas. However, in the dynamics of a plasma flow it is the pressure gradient which is important rather than the value of the pressure itself. It is shown that if one is interested in the influence of the pressure gradient on the dynamics of a plasma, it is not the quantity β which should be considered, but a similar quantity, depending on the pressure gradient. The scaling of this newly defined quantity is investigated using incompressible magnetohydrodynamic simulations in a periodic cylinder in the Reversed Field Pinch flow regime.

Domaines: Physique des plasmas [physics.plasm-ph]

Robert Chahine, Wouter J.T. Bos. On the role and value of β in incompressible MHD simulations. Physics of Plasmas, 2018, ⟨10.1063/1.5018666⟩. ⟨hal-01791962⟩