Energetic particle influence on the Earth's atmosphere

This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere

Chandra observations of Jupiter's X-ray auroral emission during Juno apojove 2017

Jupiter's auroral X-rays have been observed for 40 years with an unknown driver producing quasi-periodic emission, concentrated into auroral hot spots. In this study we analyze a ∼ 10 hour Chandra observation from 18:56 on June 18th 2017. We use a new Python pipeline to analyze the auroral morphology; perform timing analysis by incorporating Rayleigh testing and use in situ Juno observations to infer the magnetosphere was compressed during the Chandra interval. During this time Juno was near its apojove position of ∼ 112 RJ, on the dawn flank of the magnetosphere near the nominal magnetopause position. We present new dynamical polar plots showing an extended X-ray hot spot in the northern auroral region traversing across the jovian disk. From this morphology, we propose setting a numerical threshold of > 7 photons per 5° System III longitude × 5° latitude to define a photon concentration of the northern hot spot region. Our timing analysis finds two significant quasi-periodic oscillations (QPOs) of ∼ 37 and ∼ 26 minutes within the extended northern hot spot. No statistically significant QPOs were found in the southern X-ray auroral emission. The Rayleigh test is combined with Monte Carlo simulation to find the statistical significance of any QPOs found. We use a flux equivalence mapping model to trace the possible origin of the QPOs, and thus the driver, to the dayside magnetopause boundary