36 research outputs found

    Interactions between energetic electrons and realistic whistler mode waves in the Jovian magnetosphere

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    The role of plasma waves in shaping the intense Jovian radiation belts is not well understood. In this study we use a realistic wave model based on an extensive survey from the Plasma Wave Investigation on the Galileo spacecraft to calculate the effect of pitch angle and energy diffusion on Jovian energetic electrons due to upper and lower band chorus. Two Earth-based models, the Full Diffusion Code and the Versatile Electron Radiation Belt code, are adapted to the case of the Jovian magnetosphere and used to resolve the interaction between chorus and electrons at L = 10. We also present a study of the sensitivity to the latitudinal wave coverage and initial electron distribution. Our analysis shows that the contribution to the electron dynamics from upper band chorus is almost negligible compared to that from lower band chorus. For 100 keV electrons, we observe that diffusion leads to redistribution of particles toward lower pitch angles with some particle loss, which could indicate that radial diffusion or interchange instabilities are important. For energies above >500 keV, an initial electron distribution based on observations is only weakly affected by chorus waves. Ideally, we would require the initial electron phase space density before transport takes place to assess the importance of wave acceleration, but this is not available. It is clear from this study that the shape of the electron phase space density and the latitudinal extent of the waves are important for both electron acceleration and loss

    JIRAM, the Jovian Infrared Auroral Mapper

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    JIRAM is an imager/spectrometer on board the Juno spacecraft bound for a polar orbit around Jupiter. JIRAM is composed of IR imager and spectrometer channels. Its scientific goals are to explore the Jovian aurorae and the planet's atmospheric structure, dynamics and composition. This paper explains the characteristics and functionalities of the instrument and reports on the results of ground calibrations. It discusses the main subsystems to the extent needed to understand how the instrument is sequenced and used, the purpose of the calibrations necessary to determine instrument performance, the process for generating the commanding sequences, the main elements of the observational strategy, and the format of the scientific data that JIRAM will produce

    Worst Case Earth Charging Environment

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    Review of an Internal Charging Code, NUMIT

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    Processing tools refinement for the JIRAM arrival to Jupiter

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    Community-based dietary and physical activity interventions in low socioeconomic groups in the UK: a mixed methods systematic review

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    Objective: Low socioeconomic status (SES) is a risk factor for type 2 diabetes and changes in diet and physical activity can prevent diabetes. We assessed the effectiveness and acceptability of community-based dietary and physical activity interventions among low-SES groups in the UK. Method: We searched relevant databases and web resources from 1990 to November 2009 to identify relevant published and grey literature using an iterative approach, focusing on UK studies. Results: Thirty-five relevant papers (nine quantitative, 23 qualitative and three mixed methods studies) were data extracted, quality assessed and synthesised using narrative synthesis and thematic analysis. The relationship between interventions and barriers and facilitators was also examined. Dietary/nutritional, food retail, physical activity and multi-component interventions demonstrated mixed effectiveness. Qualitative studies indicated a range of barriers and facilitators, which spanned pragmatic, social and psychological issues. The more effective interventions used a range of techniques to address some surface-level psychological and pragmatic concerns, however many deeper-level social, psychological and pragmatic concerns were not addressed. Conclusion: Evidence on the effectiveness of community-based dietary and physical activity interventions is inconclusive. A range of barriers and facilitators exist, some of which were addressed by interventions but some of which require consideration in future research
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