Charged dust close to outer mean-motion resonances in the heliosphere

Abstract

We investigate the dynamics of charged dust close to outer meanmotion resonances with planet Jupiter. The importance of the interplanetary magnetic field on the orbital evolution of dust is clearly demonstrated. New dynamical phenomena are found that do not exist in the classical problem of uncharged dust. We find changes in the orientation of the orbital planes of dust particles, an increased amount of chaotic orbital motions, sudden 'jumps' in the resonant argument, and a decrease in time of temporary capture due to the Lorentz force. Variations in the orbital planes of dust grain orbits are found to be related to the angle between the orbital angular momentum and magnetic axes of the heliospheric field and the rotation rate of the Sun. These variations are bound using a simplified model derived from the full dynamical problem using first order averaging theory. It is found that the interplanetary magnetic field does not affect the capture process, that is still dominated by the other non-gravitational forces. Our study is based on a dynamical model in the framework of the inclined circular restricted three-body problem. Additional forces include solar radiation pressure, solar wind drag, the Poynting-Robertson effect, and the influence of a Parker spiral type interplanetary magnetic field model. The analytical estimates are derived on the basis of Gauss' form of planetary equations of motion. Numerical results are obtained by simulations of dust grain orbits together with the system of variational equations. Chaotic regions in phase space are revealed by means of Fast Lyapunov Chaos Indicators.

Latitudinal variations of charged dust in co-orbital resonance with Jupiter

“…The orbital motion of charged dust results in a Lorentz force term in the equations of motion which acts normal to the orbital plane of the dust grains, leading to perturbations of the orbit. The present study is motivated by recent findings in Liu & Schmidt (2018a), Liu & Schmidt (2018b), and can be seen as a continuation of previous studies: While the focus in Lhotka et al (2016) was the role of the normal component of the interplanetary magnetic field on the radial drift of particle motions, the role of outer mean motion resonances has been investigated in Lhotka & Galeş (2019). In Zhou et al (2021); extensive numerical studies are used to investigate the role of the interplanetary magnetic field on the location and extent of the 1:1 mean motion resonance (MMR) for co-orbital dust with a planet (Jupiter and Venus), yielding interesting results on the asymmetry between the Lagrange points L 4 and L 5 .…”

“…The full expression of the Lorentz force used in the computations is adopted from Eq. 16 in Lhotka & Galeş (2019) in the form of…”

“…Fitzpatrick (2016). In Lhotka & Galeş (2019), the authors have been able to isolate those terms of the equations, which do not average out on longer timescales, from the full solution. As it was solely the normal component of the magnetic field causing long-term oscillations, only i and Ω are the dynamically relevant terms for our semi-analytical model.…”

“…As it was solely the normal component of the magnetic field causing long-term oscillations, only i and Ω are the dynamically relevant terms for our semi-analytical model. The equations of Lhotka & Galeş (2019) are implemented here in the form of…”

Latitudinal dynamics of co-orbital charged dust in the heliosphere

“…Dust in space becomes positively charged by the photo-electric effect (Lhotka et al 2020). Orbital motions in the IMF therefore lead to a non-negligible Lorentz force term that affects the orbits of the charged particles in various ways: Lhotka et al (2016) showed that the normal component of the IMF may affect the radial drift towards the Sun, and the destabilising effect of the IMF on particles trapped in mean motion resonances (MMR) was demonstrated in Lhotka & Galeş (2019). Non-gravitational effects may also lead to an asymmetry between the location and size of the resonance locations L 4 and L 5 as has been shown for charged IDPs in the vicinity of Venus in Zhou et al (2021) and of Jupiter in Lhotka & Zhou (2022).…”