Statistics of the variations of the high-energy electron population between 7 and 28 jovian radii as measured by the Galileo spacecraft

Jun, I.; Garrett, Henry; Swimm, Randall T.; Evans, R. W.; Clough, Gene

doi:10.1016/j.icarus.2005.01.022

Cited by 37 publications

(35 citation statements)

References 6 publications

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“…Based on Galileo Energetic Particle Detector data, electron fluxes in the 1.5-10 MeV and > 2 MeV and >11 MeV ranges tend to increase inward of Europa's orbit [10]. This trend is consistent with our knowledge of radiation belt structure where the most energetic particles tend to be held more closely to the planet.…”

Section: Io Radiation Environmentsupporting

confidence: 81%

Io Volcano Observer's (IVO) integrated approach to optimizing system design for radiation challenges

Adams

Hibbard

Turtle

et al. 2012

2012 IEEE Aerospace Conference

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One of the major challenges for a mission to the Jovian system is the radiation tolerance of the spacecraft (S/C) and the payload. Moreover, being able to achieve science observations with high signal to noise ratios (SNR), while passing through the high flux radiation zones, requires additional ingenuity on the part of the instrument provider. Consequently, the radiation mitigation is closely intertwined with the payload, spacecraft and trajectory design, and requires a systems-level approach. This paper presents a design for the Io Volcano Observer (IVO), a Discovery mission concept that makes multiple close encounters with Io while orbiting Jupiter. The mission aims to answer key outstanding questions about Io, especially the nature of its intense active volcanism and the internal processes that drive it. The payload includes narrow-angle and wide-angle cameras (NAC and WAC), dual fluxgate magnetometers (FGM), a thermal mapper (ThM), dual ion and neutral mass spectrometers (INMS), and dual plasma ion analyzers (PIA). The radiation mitigation is implemented by drawing upon experiences from designs and studies for missions such as the Radiation Belt Storm Probes (RBSP) and Jupiter Europa Orbiter (JEO). At the core of the radiation mitigation is IVO's inclined and highly elliptical orbit, which leads to rapid passes through the most intense radiation near Io, minimizing the total ionizing dose (177 krads behind 100 mils of Aluminum with radiation design margin (RDM) of 2 after 7 encounters). The payload and the spacecraft are designed specifically to accommodate the fast flyby velocities (e.g. the spacecraft is radioisotope powered, remaining small and agile without any flexible appendages). The science instruments, which collect the majority of the highpriority data when close to Io and thus near the peak flux, also have to mitigate transient noise in their detectors. The cameras use a combination of shielding and CMOS detectors with extremely fast readout to minimize noise. INMS microchannel plate detectors and PIA channel electron multipliers require additional shielding. The FGM is not sensitive to noise induced by energetic particles and the ThM microbolometer detector is nearly insensitive. Detailed SNR calculations are presented. To facilitate targeting agility, all of the spacecraft components are shielded separately since this approach is more mass efficient than using a radiation vault. IVO uses proven radiationhardened parts (rated at 100 krad behind equivalent shielding of 280 mils of Aluminum with RDM of 2) and is expected to have ample mass margin to increase shielding if needed.

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Section: Io Radiation Environmentsupporting

confidence: 81%

Io Volcano Observer's (IVO) integrated approach to optimizing system design for radiation challenges

Adams

Hibbard

Turtle

et al. 2012

2012 IEEE Aerospace Conference

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“…Electron integral fluxes I 4 π ( E > E 0 ) at Jupiter measured by the Galileo Energetic Particle Detector (EPD) [ Jun et al , 2005] for E 0 = 1.5, 11 MeV, as a function of L shell, together with corresponding limiting profiles for the indicated values of s , l .…”

Section: Comparison Of Stably Trapped Flux Limits With Datamentioning

confidence: 99%

“…(right) Electron integral fluxes I 4 π ( E > E 0 ) at Jupiter measured by the Galileo Energetic Particle Detector (EPD) [ Sorensen et al , 2005; Jun et al , 2005] for the specified energies E 0 , as a function of L shell, together with corresponding limiting profiles for s = 0.3, l = 1.5. (left) Corresponding to the right panel, minimum resonant energy E * for gyroresonant interaction with whistler mode waves with a positive growth rate.…”

Section: Comparison Of Stably Trapped Flux Limits With Datamentioning

confidence: 99%

“…[36] Results (64), (65) and (67) are valid in the nonrelativistic approximation in which case the coefficients A, C and D are given by equations (60), (61) and (62).The nonrelativistic form of result (66) is [Jun et al, 2005] for E 0 = 1.5, 11 MeV, as a function of L shell, together with corresponding limiting profiles (67) for the indicated values of s, l.…”

Section: Jupitermentioning

confidence: 99%

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Limit on stably trapped particle fluxes in planetary magnetospheres

2009

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[1] We reexamine the Kennel-Petschek concept of self-limitation of stably trapped particle fluxes in a planetary magnetosphere. In contrast to the original Kennel-Petschek formulation, we carry out a fully relativistic analysis. In addition, we replace the wave reflection criterion in the Kennel-Petschek theory by the condition that the limit on the stably trapped particle flux is attained in the steady state condition of marginal stability when electromagnetic waves generated at the magnetic equator acquire a specified gain over a given convective growth length. We derive relativistic formulae for the limiting electron integral and differential fluxes for a general planetary radiation belt at a given L shell. The formulae depend explicitly on the spectral index and pitch angle index of the assumed particle distribution and on the ratio of the electron gyrofrequency to the electron plasma frequency. We compare the theoretical limits on the trapped flux with observed energetic electron fluxes at Earth, Jupiter, and Uranus.

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“…Specifically, it is the Divine model augmented by the Galileo high energy electron data [1,2]. In addition, the Galileo data are also used to predict a statistical radiation environment [3]. These data, together with a theoretical calculation, was carried out specifically to characterize the environment in the near vicinity of Europa [4].…”

Section: Radiation Environments and Shielding Approach For Jupiter Eumentioning

confidence: 99%

Radiation environments and shielding approach for Jupiter Europa Orbiter (JEO)

Jun

Clark

Yan

et al. 2009

2009 European Conference on Radiation and Its Effects on Components and Systems

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Statistics of the variations of the high-energy electron population between 7 and 28 jovian radii as measured by the Galileo spacecraft

Cited by 37 publications

References 6 publications

Io Volcano Observer's (IVO) integrated approach to optimizing system design for radiation challenges

Io Volcano Observer's (IVO) integrated approach to optimizing system design for radiation challenges

Limit on stably trapped particle fluxes in planetary magnetospheres

Radiation environments and shielding approach for Jupiter Europa Orbiter (JEO)

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