Sulla influenza dell'effetto Hall nella propagazione di onde magnetofluidodinamiche iu un fluido incomprimibile

Mattei, Giulio

doi:10.1007/bf02413639

Cited by 9 publications

(6 citation statements)

References 35 publications

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“…being, in this case b = ±jkj. The fact that linearized Alfvén waves in HMHD are circularly polarized was pointed out by Mattei [1969]. Moreover, the dispersion relation obtained, if V 0 is null and for right polarization, is…”

Section: Alfvén Waves In Hall Magnetohydrodynamics (Hmhd)mentioning

confidence: 86%

“…If the perturbation on magnetic induction field can be written the current density fulfills the condition given by if Thus defining two versors 1 and 2 perpendicular to k , the phase between the two components of the perturbation on the magnetic induction field must be π/2: being, in this case b = ±∣ k ∣. The fact that linearized Alfvén waves in HMHD are circularly polarized was pointed out by Mattei [1969]. Moreover, the dispersion relation obtained, if V 0 is null and for right polarization, is In the limit for short wavelengths ( k ≫ ω pi / c , where ω pi is the ion plasma frequency) one obtains the whistler mode.…”

Section: Alfvén Waves In Hall Magnetohydrodynamics (Hmhd)mentioning

confidence: 99%

“…Since Alfvén wings are closely related to Alfvén waves, we start by searching the existence, in this case, of Alfvénic perturbations. Alfvén waves with a Hall term have been studied by other authors [ Mattei , 1969; Ovenden et al , 1983; Woodward and McKenzie , 1994a, 1994b; Pokhotelov et al , 1996], but they linearize the magnetohydrodynamic equations or impose particular dependencies for the perturbations. In a similar way as it is done by Sallago and Platzeck [2000], instead of linearizing the magnetohydrodynamic equations and searching monochromatic waves, we impose the conditions that the perturbation propagate without distortion with a group velocity parallel to the background magnetic induction field, in the reference system in which the plasma is locally at rest, the perturbation be incompressible, there exist a relation between the velocity and induction magnetic field perturbations, and a magnitude called total generalized pressure remain constant in the disturbed region.…”

Section: Introductionmentioning

confidence: 99%

“…This condition, called the “polarization condition,” relates the current density and its curl. In the linearized case for small perturbations and monochromatic waves, this condition means that the perturbation on magnetic induction field must be circularly polarized [ Mattei , 1969; Pokhotelov et al , 1996]. Owing to this condition it is not possible to impose the adiabaticity condition because the system would result overdetermined; as a result, the plasma pressure is not constant in the perturbed region.…”

Section: Introductionmentioning

confidence: 99%

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Alfvén waves and wings in Hall magnetohydrodynamics

Sallago

Platzeck

2004

J. Geophys. Res.

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[1] The problem of a conducting body moving in a magnetized plasma when the electronic pressure and Hall terms in Ohm's law cannot be neglected is analyzed in the magnetohydrodynamic approximation. Since Alfvén wings are closely related to Alfvén waves, the influence of these terms in the propagation of Alfvénic perturbations of large amplitude is studied. Instead of linearizing the magnetohydrodynamic equations and searching monochromatic waves, the conditions that the group velocity be parallel to the background magnetic induction field, in the reference system in which the plasma is locally at rest, that the perturbation be incompressible, that the perturbations in velocity and the magnetic induction field be related, and that a magnitude connected to the pressure remain constant are imposed. It is shown that large-amplitude Alfvén waves can propagate in homogeneous plasmas if a ''polarization condition'' on the current density is fulfilled. The value of their group velocity is different from the value that it takes when simple Ohm's law is used. On the other hand, the methodology of stream functions is used for the analysis of Alfvén wings. Their existence, when the Hall term in Ohm's law is relevant, is proved, and the relations among the plasma pressure, induction magnetic field, velocity, and electric current density in the wing are found. The present results can be applied, as an approximation, to spacecraft or space tethers moving in a circular orbit if one can consider that the density and the magnetic induction field do not change as the source is orbiting and if the influence of partial ionization can be neglected.

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Section: Alfvén Waves In Hall Magnetohydrodynamics (Hmhd)mentioning

confidence: 86%

Section: Alfvén Waves In Hall Magnetohydrodynamics (Hmhd)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Alfvén waves and wings in Hall magnetohydrodynamics

Sallago

Platzeck

2004

J. Geophys. Res.

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“…Las ondas de Alfvén con término Hall han sido estudiadas por otros autores como Mattei [7], Woodward y McKenzie [8,9], Pokhotelov et al [10], entre otros. Ellos linealizan el sistema de ecuaciones de la magnetohidrodinámica o imponen dependencias particulares para las perturbaciones.…”

Section: Introductionunclassified

Large Amplitude Alfvén Waves in Partially Ionized Plasmas

Sallago¹

2022

AnAFA

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In this paper it is analyzed the propagation of large amplitude Alfvén waves in partially ionized plasmas (PIP) when electronic pressure, Hall and ambipolar terms of Ohm’s law are taken into account. Instead of linearizing and developing the perturbation in monochromatic waves, it is proposed that the perturbation satisfy the Alfvén wave’s conditions. As a result, a solution is found that in the fully ionized limit, it coincides with Sallago and Platzeck solution for Alfvénwaves in Hall magnetohydrodynamics (doi:10.1029/2003JA009920 ). Furthermore, if electronic pressure and Hall terms are null, in the linearized limit, the damping is equal to the one described by De Pontieu, B. Martens, P. C. H. and Hudson, H. S. (DOI = 10.1086/322408), if one imposes that the plasma is a perfect conductor.

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