Variational principle with singular perturbation of hall magnetohydrodynamics
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)
The Hall magnetohydrodynamics (H-MHD) model can describe an intrinsic small scale (ion skin depth l{sub i}) introduced by the Hall effect. The Hall term appears as a singular perturbation to the conventional magnetohydrodynamics (MHD) model, and hence, the MHD limit (l{sub i}{yields}0) may be singular. The H-MHD system has three constants of motion, the energy, the magnetic (electron) and ion helicities. The ion helicity is known to be 'fragile' with respect to the energy norm of the magnetic and flow fields [Z. Yoshida and S. M. Mahajan, Phys. Rev. Lett. 88, 095001 (2002)]. Under an appropriate ordering of scales, the ion helicity translates as the cross helicity that is a constant of motion of the MHD system. Conservation of the cross helicity is an essential condition to recover the macroscopic MHD picture from the H-MHD framework.
- OSTI ID:
- 20764352
- Journal Information:
- Physics of Plasmas, Vol. 12, Issue 6; Other Information: DOI: 10.1063/1.1936585; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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