Survey of Juno Observations in Jupiter's Plasma Disk: Density

• Published in: Journal of geophysical research. Space physics 2021-08, Vol.126 (8), p.n/a
• Main Authors: Huscher, E., Bagenal, F., Wilson, R. J., Allegrini, F., Ebert, R. W., Valek, P. W., Szalay, J. R., McComas, D. J., Connerney, J. E. P., Bolton, S., Levin, S. M.
• Format: Article
• Language: English
• Subjects: Depletion; Equator; Heavy ions; Ions; Jupiter; Jupiter probes; Magnetic dipoles; Magnetotails; Orbits; Oxygen; Oxygen ions; Planetary magnetospheres; Plasma; Plasma density; Plasmas (physics); Solar wind; Spacecraft; Sulfur
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2021JA029446

We explore the variation in plasma conditions through the middle magnetosphere of Jupiter with latitude and radial distance using Juno‐JADE measurements of plasma density (electrons, protons, sulfur, and oxygen ions) surveyed on Orbits 5–26 between March 2017 and April 2020. On most orbits, the densities exhibit regular behavior, mapping out a disk between 10 and 50 RJ (Jovian radii). In the disk, the heavy ions are confined close to the centrifugal equator which oscillates relative to the spacecraft due to the ∼10° tilt of Jupiter's magnetic dipole. Exploring each crossing of the plasma disk shows there are some occasions where the density profiles are smooth and well‐defined. At other times, small‐scale structures suggest temporal and/or spatial variabilities. There are some exceptional orbits where the outer regions (30–50 RJ) of the plasma disk show uniform depletion, perhaps due to enhanced ejection of plasmoids down the magnetotail, possibly triggered by solar wind compression events. Key Points On most orbits, the densities exhibit regular behavior mapping out a disk confined close to the centrifugal equator Small‐scale (∼minutes) variabilities may indicate radial transport via local instabilities Occasionally a uniformly tenuous outer disk indicates enhanced losses, perhaps triggered by solar wind compression