Dynamic Jovian Magnetosphere Responses to Enhanced Solar Wind Ram Pressure: Implications for Auroral Activities

Abstract

The main emission (ME) of the Jovian aurora is thought to be related to the current system associated with the breakdown of plasma corotation in the middle magnetosphere. According to the mainstream corotation breakdown model, the intensity of the Jovian ME is expected to decrease when the solar wind (SW) ram pressure increases, which is not fully consistent with auroral observations. In addition to the field-aligned current (FAC), Alfvénic power (AP) play an important role in regulating planetary auroral emissions. We use three-dimensional global simulations to investigate how these proxies of auroral emission respond to enhanced SW ram pressure. We found that during SW compression, both FAC and AP experience up-down-up trends, which is not revealed by any previous simulations, while could potentially explain many observations. The results suggest that different Jovian auroral activities including brightening or dimming can be observed during SW compression period.