Auroral processes in the solar system

Galand, M.; Chakrabarti, Supriya

doi:10.1029/130gm05

Cited by 19 publications

(13 citation statements)

References 164 publications

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“…For energies lower than typically 100 keV, relativistic effects (for instance bremsstrahlung and Cherenkov effect) and spallation processes [e.g., Deghfel et al , 2009] may be neglected. At these energies, the transport of protons can be described as a coupled H + /H system of kinetic Boltzmann equations, requiring the inclusion of charge‐exchange reactions, ionization and excitation mechanisms [e.g., Basu et al , 1993; Bisikalo et al , 1996; Galand and Chakrabarti , 2002; Fox et al , 2008]. In only a few studies because of its complexity, angular redistribution due to collisions and magnetic effects have been calculated, using the continuous slowing down approximation (valid in the energy range considered) to simplify the equations [ Galand et al , 1997; Simon et al , 2007].…”

Section: Focused Simulation Of Predicted Ionospheric Densities Duringmentioning

confidence: 99%

Numerical simulation of the effects of a solar energetic particle event on the ionosphere of Mars

et al. 2012

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[1] We investigate the ionospheric effects of a solar energetic particle (SEP) event at Mars, specifically the 29 September 1989 event. We use its energy spectrum and a steady state ionospheric model to simulate vertical profiles of ion and electron densities. The ionospheric response to this large event would have been readily observable. It caused electron densities to exceed 10 4 cm À3 at 30-170 km, much larger than typically observed below 100 km. It also increased the ionosphere's total electron content by half of its subsolar value and would have caused strong attenuation of radio waves. The simulated attenuation is 462 dB at 5 MHz, which demonstrates that SEP events can cause sufficient attenuation (>13 dB) to explain the lack of surface reflections in some MARSIS topside radar sounder observations. We also develop a complementary generalized approach to the study of the ionospheric effects of SEP events. This approach predicts the threshold intensities at which a SEP event is likely to produce detectable changes in electron density profiles and radio wave attenuation measurements. An event one hundred times less intense than the 29 September 1989 event produces electron densities in excess of 3000 cm À3 at 80 km, which should be measurable by radio occultation observations, and causes sufficient attenuation to eliminate MARSIS surface reflections. However, although enhancements in total electron content have been observed during SEP events, predicted enhancements in low altitude electron density were not confirmed by observations.

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Section: Focused Simulation Of Predicted Ionospheric Densities Duringmentioning

confidence: 99%

Numerical simulation of the effects of a solar energetic particle event on the ionosphere of Mars

et al. 2012

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“…This yields the so-called 'auroral emissions' defined as the photo-manifestation of the interaction of energetic, extra-atmospheric particles with an atmosphere (e.g. Bhardwaj and Gladstone 2000;Galand and Chakrabarti 2002;Fox et al 2008;Slanger et al 2008). Auroral particle degradation results in an increase in ionospheric densities and electrical conductances (e.g.…”

Section: Saturnmentioning

confidence: 99%

Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra

et al. 2014

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“…Auroral emissions observed from ground-based and Earth-orbiting observatories and from space probes offer us an extremely valuable remote-sensing of the auroral particle source. Its quantitative analysis allows the identification of the type of precipitating particles and the assessment of the incident particle characteristics in terms of mean energy and energy flux (e.g., Galand and Chakrabarti 2002;Fox et al 2008;Slanger et al 2008b). …”

Section: Auroramentioning

confidence: 99%