Effect of Meteoric Ions on Ionospheric Conductance at Jupiter

Abstract

Ionospheric Pedersen and Hall conductances play significant roles in electromagnetic coupling between the planetary ionosphere and magnetosphere. Several observations and models have suggested the existence of meteoric ions with interplanetary origins in the lower part of Jupiter’s ionosphere; however, no models have considered the contributions of meteoric ions to ionospheric conductance. This study is designed to evaluate the contribution of meteoric ions to ionospheric conductance by developing an ionospheric model combining a meteoroid ablation model and a photochemical model. We find that the largest contribution to Pedersen and Hall conductivities occurs in the meteoric ion layer at altitudes of 350–600 km due to the large concentration of meteoric ions resulting from their long lifetimes of more than 100 Jovian days. Pedersen and Hall conductances are enhanced by factors of 3 and 10, respectively, in the middle‐ and low‐latitude and auroral regions when meteoric ions are included. The distribution of Pedersen and Hall conductances becomes axisymmetric in the middle‐ and low‐latitude regions. Enhanced axisymmetric ionospheric conductance should impact magnetospheric plasma convection. The contribution of meteoric ions to the ionospheric conductance is expected to be important only on Jupiter in our solar system because of Jupiter’s intense magnetic and gravitational fields.

Magnetosphere‐Ionosphere‐Thermosphere Coupling Study at Jupiter Based on Juno's First 30 Orbits and Modeling Tools

“…For auroral conditions, however, the meteoric contribution to ionospheric conductances found by Nakamura et al. ( 2022 ) is on the order of a few tenths of mhos, negligible with respect to the conductances of several (up to 10) mhos generated by electron precipitation, as the results of the present study show.…”

“…This model neglects ionization sources other than electron precipitation, such as solar photons and also the meteoric ion contribution, which Nakamura et al. ( 2022 ) recently showed to be significant at low and middle latitudes. For auroral conditions, however, the meteoric contribution to ionospheric conductances found by Nakamura et al.…”

Strong Depletion of 13C in CO Induced by Photolysis of CO2 in the Martian Atmosphere, Calculated by a Photochemical Model

“…We use a 1D photochemical model developed by Nakamura et al (2022aNakamura et al ( , 2022b, with some modifications to the chemical processes. These solve the continuity-transport equations that govern the changes in the number density profiles of the chemical species, by numerical integration over time, until the profiles settle into steady states.…”

Simulation of Dawn‐To‐Dusk Electric Field in the Jovian Inner Magnetosphere via Region 2‐Like Field‐Aligned Current

“…The photochemical model took into account 406 chemical reactions for 55 ion species in the Jovian ionosphere based on the hydrocarbon ion chemistry described in Kim and Fox (1994) and meteoric ion chemistry described in Kim et al (2001). The list of chemical reactions used in the model is given in Appendix of Nakamura et al (2022). The EUVAC model (Richards et al, 1994) was used for the solar EUV flux to calculate photoionization rates of neutral species and the F10.7 index was assumed to be 140 corresponding to moderate solar activity.…”

“…The ionospheric potential solver can obtain the global distribution of ionospheric potential using the FAC density distribution as a source and an ionospheric conductance tensor as a coefficient by solving a Poisson equation. We have used the Jovian ionosphere model described in Nakamura et al (2022) to calculate the global distribution of ionospheric conductance under a given FAC input.…”