Energetic Plasma Injections in Jovian Inner Magnetosphere: A Simulation Study.

Outward transport of cold iogenic plasma and energetic charged particle injections are two essential aspects of mass, energy and magnetic flux circulation in the Jovian magnetosphere. However, it is unclear how these two processes interplay and how they evolve globally in the Jovian inner magnetosphere. We use the improved Rice Convection Model‐Jupiter to simulate the concurrent energetic injection and cold plasma convection in Jupiter's inner magnetosphere. The effects of plasma density, injection site location and energy of energetic particles on the plasma injection are parametrically investigated through a series of runs. The model successfully reproduces the energy‐time dispersion signature of energetic particles that may be observed by a spacecraft during an injection event. Simulation results show that the energetic injection is mainly driven by the electric field associated with the cold plasma outflow. Energetic particles are transported inward in the form of elongated fingers which appear interlaced with those of cold iogenic plasma. The injected particles are strongly modulated by the gradient/curvature drift, especially in inner regions close to the planet, and show a significant dispersion feature during the evolution. The radial velocity of the injection decreases from over 100 km/s at L = 20 RJ to less than 10 km/s at L = 10 RJ, while the related field‐aligned currents tend to increase during the inward injection. The energetic plasma density and the injection site location are found to have little effect on the plasma injection, provided that their effect on cold plasma convection is negligible. Plain Language Summary: The injection of hot plasma from the outside to the inside of the magnetosphere is commonly observed in planetary magnetospheres. At Jupiter, cold plasma originating from Jupiter's Galilean moon Io is transported outward throughout the magnetosphere via the interchange instability, which is essentially similar to the so‐called Rayleigh‐Taylor instability in hydrodynamics. In the meantime, distant flux tubes are supposed to move inward to balance the outflowing cold and dense plasma as a result of conservation of magnetic flux. The hot and tenuous particles embedded in distant flux tubes can thus be injected inward. In this article, we improve our previous Rice Convection Model‐Jupiter by including energetic plasma and use it to study both the hot plasma injection and cold plasma convection in the Jovian inner magnetosphere. Our improved model is capable of reproducing injection signatures that align with observations. We found that the outflowing cold plasma from Io plays a crucial role in the injection of hot plasma. Key Points: We simulate the concurrent energetic injection and cold iogenic plasma convection using an improved Jovian inner magnetosphere modelWe reproduce the energy‐time dispersion signature of energetic particles during an injection event by full simulations for the first timeThe energetic injection is found to be significantly affected by the outflowing cold plasma convection [ABSTRACT FROM AUTHOR]