Limits...
Comparative investigation of the energetic ion spectra comprising the magnetospheric ring currents of the solar system.

Mauk BH - J Geophys Res Space Phys (2014)

Bottom Line: Chosen for comparison are the ion spectra within these systems that are the most intense observed, specifically at 100 keV and 1 MeV.We find that Earth and Jupiter are unique in having their most intense ion spectra likely limited and sculpted by the Kennel-Petschek process.Suggestions are provided for further testing the efficacy of the differential Kennel-Petschek limit for ions using the Van Allen Probes.

View Article: PubMed Central - PubMed

Affiliation: Johns Hopkins University Applied Physics Laboratory Laurel, Maryland, USA.

ABSTRACT

Investigated here are factors that control the intensities and shapes of energetic ion spectra that make up the ring current populations of the strongly magnetized planets of the solar system, specifically those of Earth, Jupiter, Saturn, Uranus, and Neptune. Following a previous and similar comparative investigation of radiation belt electrons, we here turn our attention to ions. Specifically, we examine the possible role of the differential ion Kennel-Petschek limit, as moderated by Electromagnetic Ion Cyclotron (EMIC) waves, as a standard for comparing the most intense ion spectra within the strongly magnetized planetary magnetospheres. In carrying out this investigation, the substantial complexities engendered by the very different ion composition distributions of these diverse magnetospheres must be addressed, given that the dispersion properties of the EMIC waves are strongly determined by the ion composition of the plasmas within which the waves propagate. Chosen for comparison are the ion spectra within these systems that are the most intense observed, specifically at 100 keV and 1 MeV. We find that Earth and Jupiter are unique in having their most intense ion spectra likely limited and sculpted by the Kennel-Petschek process. The ion spectra of Saturn, Uranus, and Neptune reside far below their respective limits and are likely limited by interactions with gas and dust (Saturn) and by the absence of robust ion acceleration processes (Uranus and Neptune). Suggestions are provided for further testing the efficacy of the differential Kennel-Petschek limit for ions using the Van Allen Probes.

No MeSH data available.


Related in: MedlinePlus

(top) Saturn ion spectra replotted from Figure1. (bottom) The Kennel-Petschek analysis of the three Saturn ion spectra, comprising the Cm/CK profiles derived using equation (4).
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fig08: (top) Saturn ion spectra replotted from Figure1. (bottom) The Kennel-Petschek analysis of the three Saturn ion spectra, comprising the Cm/CK profiles derived using equation (4).

Mentions: The KP analyses for the Saturn spectra shown in Figure1 and replotted in Figure8 (top) are presented in Figure8 (bottom). Saturn is clearly a very different place in that its spectra do not challenge the KP limit at any energy. This result for ions is consistent with the results for electrons. As with the electrons, we assume that the copious presence of neutral gas and dust degrades the ion spectra faster than the ions can be accelerated to the highest levels [Paranicas et al., 2008].


Comparative investigation of the energetic ion spectra comprising the magnetospheric ring currents of the solar system.

Mauk BH - J Geophys Res Space Phys (2014)

(top) Saturn ion spectra replotted from Figure1. (bottom) The Kennel-Petschek analysis of the three Saturn ion spectra, comprising the Cm/CK profiles derived using equation (4).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4497457&req=5

fig08: (top) Saturn ion spectra replotted from Figure1. (bottom) The Kennel-Petschek analysis of the three Saturn ion spectra, comprising the Cm/CK profiles derived using equation (4).
Mentions: The KP analyses for the Saturn spectra shown in Figure1 and replotted in Figure8 (top) are presented in Figure8 (bottom). Saturn is clearly a very different place in that its spectra do not challenge the KP limit at any energy. This result for ions is consistent with the results for electrons. As with the electrons, we assume that the copious presence of neutral gas and dust degrades the ion spectra faster than the ions can be accelerated to the highest levels [Paranicas et al., 2008].

Bottom Line: Chosen for comparison are the ion spectra within these systems that are the most intense observed, specifically at 100 keV and 1 MeV.We find that Earth and Jupiter are unique in having their most intense ion spectra likely limited and sculpted by the Kennel-Petschek process.Suggestions are provided for further testing the efficacy of the differential Kennel-Petschek limit for ions using the Van Allen Probes.

View Article: PubMed Central - PubMed

Affiliation: Johns Hopkins University Applied Physics Laboratory Laurel, Maryland, USA.

ABSTRACT

Investigated here are factors that control the intensities and shapes of energetic ion spectra that make up the ring current populations of the strongly magnetized planets of the solar system, specifically those of Earth, Jupiter, Saturn, Uranus, and Neptune. Following a previous and similar comparative investigation of radiation belt electrons, we here turn our attention to ions. Specifically, we examine the possible role of the differential ion Kennel-Petschek limit, as moderated by Electromagnetic Ion Cyclotron (EMIC) waves, as a standard for comparing the most intense ion spectra within the strongly magnetized planetary magnetospheres. In carrying out this investigation, the substantial complexities engendered by the very different ion composition distributions of these diverse magnetospheres must be addressed, given that the dispersion properties of the EMIC waves are strongly determined by the ion composition of the plasmas within which the waves propagate. Chosen for comparison are the ion spectra within these systems that are the most intense observed, specifically at 100 keV and 1 MeV. We find that Earth and Jupiter are unique in having their most intense ion spectra likely limited and sculpted by the Kennel-Petschek process. The ion spectra of Saturn, Uranus, and Neptune reside far below their respective limits and are likely limited by interactions with gas and dust (Saturn) and by the absence of robust ion acceleration processes (Uranus and Neptune). Suggestions are provided for further testing the efficacy of the differential Kennel-Petschek limit for ions using the Van Allen Probes.

No MeSH data available.


Related in: MedlinePlus