Investigation Of The Magnetosonic Waves In Magnetized Plasmas Based On Multi-fluid Model

Plasma can be regarded as a conductive fluid where magnetic pressure and thermal pressure generate two distinct types of waves: Alfvén waves and acoustic waves,respectively.The magnetosonic waves are produced by both pressures mentioned above acting as the restorative force,and prevalent in space and astrophysical plasma.The propagation direction of the magnetosonic wave is nearly perpendicular to the external magnetic field.These waves have many applications,such as contributing to proton heating in the Earth’s magnetosphere and playing a crucial role in plasma heating and energy transport in various environments.In this paper,we explore magnetosonic waves in both electron-ion plasma and dusty plasma.In electron-ion plasma,we obtain the dispersion relation and phase velocity of linear magnetosonic waves by using linear wave theory.Our findings demonstrate that the phase velocity of magnetosonic waves is dependent on the Alfvén velocity produced by magnetic pressure and the acoustic velocity produced by thermal pressure.We also study magnetosonic solitary waves of arbitrary amplitude and find that the strong magnetic field in the upstream and downstream regions of the Venusian bow shock wave causes the magnetic pressure to surpass the thermal pressure,with the propagation velocity of the magnetosonic solitary wave varying from the minimum value(Alfvén velocity)to the maximum value(1.24 times Alfvén velocity).The value of the disturbed magnetic field is from the minimum value of zero to the maximum value of the external magnetic field.We also examine the dispersion relations of linear magnetosonic waves in three different environments of dusty plasma: the typical ionosphere,the interior of a White Dwarf,and the dense dusty plasma cloud of Saturn’s rings.In each of the three environments,there exist two dispersion relations for linear magnetosonic waves.One of the dispersion relations corresponds to the higher frequencies and the other corresponds to the lower frequencies.When the wave length of the perturbed wave is in a certain wavelength range,the frequency of the perturbed wave is close to a specific frequency.We discuss the effect of the inertia of electrons and ions on the dispersion relations in these environments.Our research shows that the effect of the inertia of electrons and ions cannot be neglected in the ionospheric environment and the interior of a White Dwarf,and for higher frequency magnetosonic waves in the dense dusty plasma cloud of Saturn’s rings.However,for lower frequency magnetosonic waves in the dense dusty plasma cloud of Saturn’s rings,the inertia of electrons and ions can be neglected.