Particle-in-cell simulations of ion-acoustic waves with application to Saturn's magnetosphere

Abstract

Using a particle-in-cell simulation, the dispersion and growth rate of the ion-acoustic mode are investigated for a plasma containing two ion and two electron components. The electron velocities are modelled by a combination of two kappa distributions, as found in Saturn's magnetosphere. The ion components consist of adiabatic ions and an ultra-low density ion beam to drive a very weak instability, thereby ensuring observable waves. The ion-acoustic mode is explored for a range of parameter values such as κ, temperature ratio, and density ratio of the two electron components. The phase speed, frequency range, and growth rate of the mode are investigated. Simulations of double-kappa two-temperature plasmas typical of the three regions of Saturn's magnetosphere are also presented and analysed.

Unstable mode of ion-acoustic waves with two temperature q-nonextensive distributed electrons

“…To validate our numerical analysis, we choose some typical parameters of Saturn's outer magnetosphere [58,59] as observed from the spacecraft. The observations showed that the Saturn's magnetosphere has three regions, the inner region [D (9-10)ρ s ], the middle region [D ∼ (7-14)ρ s ] and the outer region of magnetosphere [D ∼ (12-20)ρ s ] with ρ s (= 60270 km) represents radius of the Saturn.…”

Dust Acoustic Solitons in Saturn’s Dust-Filled Magnetosphere

“…The soliton solution is found from the relation (12) where ϕ ξ is the first derivative of function ϕ with respect to ξ. n n e Below, results are given for calculations that were carried out for the following parameters of Saturn's magnetosphere (see [4,6,9]): n i0 = 10 cm -3 , T i = 100 K, T ec = 10 eV, T eh = 700 eV, , and κ c = κ h = 2.…”

“…Also based on the data collected by the Voyager 1 spacecraft [5], it was shown that waves exist in the magnetospheric plasma of Saturn. Theoretical studies of ion acoustic waves in Saturn's magnetosphere were carried out in [6]. The dusty plasma in the vicinity of Saturn's satellite Enceladus was discovered during the Cassini mission [2,3].…”

Experimental study on controlled production of two-electron temperature plasma

“…In a kinetic simulation of IA wave propagation in two-electron temperature plasma, it has been found that the presence of a significant population of hot electron enhances the growth of IA wave. In contrast, the decrease in the effective electron temperature contributes to damping [34]. To observe the effect of hot electrons, an ion-acoustic wave is excited in the system, the details of which have already been described in section 2.…”