The parametric instability of a monochromatic shear Alfvén wave in oblique propagation with respect the ambient magnetic field is investigated in a kinetic regime, performing one-dimensional (1-D) and two-dimensional (2-D) hybrid simulations. The parallel component of the mother wave is found to be subject to a parametric decay which excites an ion-acoustic wave along the magnetic field and a backward propagating daughter shear Alfvén wave, as in the instability for a purely parallel mother wave. At the same time, the acoustic wave generation supports the acceleration of a velocity beam in the ion distribution function, due to the non-linear trapping of protons. Moreover, the instability leads to the generation of broad band oblique spectra of coupled Alfvénic and compressive modes with variable perpendicular wavevectors, and, as a consequence, the magnetic field after saturation is characterized by a strong transverse modulation.

Parametric decay of linearly polarized shear Alfvén waves in oblique propagation: One and two-dimensional hybrid simulations / L. Matteini; S. Landi; L. Del Zanna; M. Velli; P. Hellinger. - In: GEOPHYSICAL RESEARCH LETTERS. - ISSN 0094-8276. - STAMPA. - 37:(2010), pp. L20101-L20101-4. [10.1029/2010GL044806]

Parametric decay of linearly polarized shear Alfvén waves in oblique propagation: One and two-dimensional hybrid simulations

MATTEINI, LORENZO;LANDI, SIMONE;DEL ZANNA, LUCA;VELLI, MARCO;
2010

Abstract

The parametric instability of a monochromatic shear Alfvén wave in oblique propagation with respect the ambient magnetic field is investigated in a kinetic regime, performing one-dimensional (1-D) and two-dimensional (2-D) hybrid simulations. The parallel component of the mother wave is found to be subject to a parametric decay which excites an ion-acoustic wave along the magnetic field and a backward propagating daughter shear Alfvén wave, as in the instability for a purely parallel mother wave. At the same time, the acoustic wave generation supports the acceleration of a velocity beam in the ion distribution function, due to the non-linear trapping of protons. Moreover, the instability leads to the generation of broad band oblique spectra of coupled Alfvénic and compressive modes with variable perpendicular wavevectors, and, as a consequence, the magnetic field after saturation is characterized by a strong transverse modulation.
2010
37
L20101
L20101-4
L. Matteini; S. Landi; L. Del Zanna; M. Velli; P. Hellinger
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/412452
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