![]() ![]() ![]() The divergence between the axisymmetric theoretical model and the observations suggest that other mechanisms may play a role in regulating the response of Jovian auroral emissions during dynamic periods such as enhanced SW ram pressure. In addition, Bonfond et al., 2020 summarized the divergence between corotation model and observation events in the aspect of dawn/dusk asymmetries, global auroral brightening with SWC, etc. Also, Jupiter's auroral UV emissions, especially in the polar and main ones, are found to be enhanced during SWC (e.g., Nichols et al., 2009, 2017 Yao et al., 2022). However, ultraviolet (UV) emissions, which can be separated into polar emissions, MEs, and equatorward emissions (Nichols et al., 2009), are relatively more direct and persuasive because Jupiter's UV auroras can be observed directly with high spatial and temporal resolution equipment such as Hubble Space Telescope (HST). For example, enhancements of the auroral emissions in radio, infrared, emission, and X-ray wavelengths are found during solar wind compression (SWC) periods (e.g., Baron et al., 1996 Connerney & Satoh, 2000 Dunn et al., 2016 Gurnett et al., 2002 Hess et al., 2014 Sinclair et al., 2019), but the interpretations for these wavelengths are not straightforward because of a lack of spatial resolution and temporal sampling. However, this theoretical prediction of reduced magnetospheric current is inconsistent with existing Jovian auroral observations during enhanced SW ram pressure events. Thus, the intensity of the Jovian main auroral emission is expected to decrease when under enhanced SW ram pressure. Considering the conservation of angular momentum, when the magnetosphere moves inward, for example, due to enhanced solar wind (SW) ram pressure events, the angular velocities of the plasma is expected to increase, leading to a reduced velocity shear and a decrease in the corotation-related currents (e.g., Cowley & Bunce, 2001 Cowley et al., 2007 Hill, 1979 Southwood & Kivelson, 2001). To the first order, the large-scale magnetospheric current system associated with the breakdown of plasma corotation in the middle Jovian magnetosphere is thought to drive the main emission (ME) of the Jovian aurora (e.g., Cowley & Bunce, 2001 Hill, 2001 Southwood & Kivelson, 2001). Jupiter has the largest magnetosphere and the most intense auroral emissions in the solar system. ![]()
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