Simulation of Dawn‐to‐Dusk Electric Field in the Jovian Inner Magnetosphere via Region 2‐like Field‐Aligned Current
Résumé
The presence of the dawn-to-dusk electric field of about 4 mV/m in the Jovian inner
magnetosphere and its response to the enhancement of the solar wind dynamic pressure are still a mystery of
the rotation-dominated Jovian magnetosphere. Previous studies have suggested that magnetosphere-ionosphere
(M-I) coupling via Region 2-like (R2-like) field-aligned current (FAC) could be the origin of the Jovian
dawn-to-dusk electric field. This study investigates whether the dawn-to-dusk electric field is formed from this
scenario by using a Jovian ionosphere model and a two-dimensional ionospheric potential solver. Our results
show that the dawn-dusk asymmetry in the ionospheric potential form even at middle latitudes and that the
dawn-to-dusk electric field is induced in the inner magnetosphere if the electric potential is mapped to the
magnetospheric equatorial plane. Around the Io orbit, the calculated electric field strength for the ionosphere
without meteoroid influx is too large, 200 mV/m at dawn and 88 mV/m at dusk. One of the solutions is to
consider long-lived meteoric ions in the Jovian ionosphere, which reduce the electric field strength to 15 mV/m
at dawn and 12 mV/m at dusk. The model also shows that the electric field strength increases with the intensity
of R2-like FAC, consistent with its response to the solar wind dynamic pressure observed by the Hisaki satellite.
Domaines
Planète et Univers [physics]
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JGR Space Physics - 2023 - Nakamura - Simulation of Dawn‐To‐Dusk Electric Field in the Jovian Inner Magnetosphere via.pdf (5.23 Mo)
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