Meteoric Ions in the Ionosphere of Jupiter

Kim, Yong Ha; Pesnell, W. D.; Grebowsky, J. M.; Fox, Jane L.

doi:10.1006/icar.2001.6590

Cited by 37 publications

(45 citation statements)

References 75 publications

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“…We neglect both the momentum transfer between H 2 and electron through collision and the thermal velocity of the molecule. This assumption is valid because the neutral temperature is around 1000 K even when it goes up by auroral heating on the basis of calculation results of the JIM (Achilleos et al, 1998 Kim et al (2001) to be estimated from observations of the Galileo spacecraft.…”

Section: Model Descriptionmentioning

confidence: 99%

Parameterization of ionization rate by auroral electron precipitation in Jupiter

Hiraki

Tao

2008

Ann. Geophys.

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Abstract. We simulate auroral electron precipitation into the Jovian atmosphere in which electron multi-directional scattering and energy degradation processes are treated exactly with a Monte Carlo technique. We make a parameterization of the calculated ionization rate of the neutral gas by electron impact in a similar way as used for the Earth's aurora. Our method allows the altitude distribution of the ionization rate to be obtained as a function of an arbitrary initial energy spectrum in the range of 1-200 keV. It also includes incident angle dependence and an arbitrary density distribution of molecular hydrogen. We show that there is little dependence of the estimated ionospheric conductance on atomic species such as H and He. We compare our results with those of recent studies with different electron transport schemes by adapting our parameterization to their atmospheric conditions. We discuss the intrinsic problem of their simplified assumption. The ionospheric conductance, which is important for Jupiter's magnetosphere-ionosphere coupling system, is estimated to vary by a factor depending on the electron energy spectrum based on recent observation and modeling. We discuss this difference through the relation with fieldaligned current and electron spectrum.

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Section: Model Descriptionmentioning

confidence: 99%

Parameterization of ionization rate by auroral electron precipitation in Jupiter

Hiraki

Tao

2008

Ann. Geophys.

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“…Collisions with H atoms and vibrational energy transfer from H 2 (v≥ 1) may play significant roles in reducing the non-LTE effects of H + 3 emission in the Jovian ionosphere at high altitudes. The Jovian thermosphere temperature is higher above the peak of the H + 3 density profile near 600 km (Kim et al, 2001). The fraction of H + 3 emission from high altitudes could increase rapidly if non-LTE effects are reduced, as noted by Melin et al (2005).…”

Section: Resultsmentioning

confidence: 82%

NON-LTE EFFECTS ON THE H₃⁺ROVIBRATIONAL POPULATION IN THE JOVIAN IONOSPHERE

Kim¹

2012

Journal of The Korean Astronomical Society

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We investigate non-LTE effects on the H + 3 level populations to help the analysis of the observed 2 and 3.5 micron H + 3 emissions from the Jovian ionosphere. We begin by constructing a simple threelevel model, in order to compute the intensity ratio of the R(3,4) line in the hot band to the Q(1,0) line in the fundamental band, which have been observed in the Jovian auroral regions. We find that non-LTE effects produce only small changes in the intensity ratios for ambient H 2 densities less than or equal to 5×10 11 cm −3 . We then construct two comprehensive models by including all the collisional and radiative transitions between pairs of more than a thousand known H + 3 rovibrational levels with energies less than 10000 cm −1 . By employing these models, we find that the intensity ratios of the lines in the hot and fundamental bands are affected greatly by non-LTE effects, but the details depend sensitively on the number of collisional and radiative transitions included in the models. Non-LTE effects on the rovibrational population become evident at about the same ambient H 2 densities in the comprehensive models as in the three-level model. However, the models show that rotational temperatures derived from the intensities of rotational lines in the ν 2 and 2ν 2 bands may differ significantly from the ambient temperatures in the non-LTE regime. We find that significant non-LTE effects appear near and above the H + 3 peak, and that the kinetic temperatures in the Jovian thermospheric temperatures derived from the observed line ratios in the 2 and 3.5 micron H + 3 emissions are highly model dependent.

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“…Fe along with Mg are the dominant meteoroid metal constituents. The difference in the distribution of the two metal ion species on Jupiter is due to the differing reactions of the two metals with hydrocarbons (as discussed in Kim et al (2000). The chemistry on Mars and Earth for these two species does not lead to any such significant differences in their altitude distributions.…”

Section: The Focused Flux Is Equal To Su[l+(vesca_u):]mentioning

confidence: 97%

“…(Grebowsky and Pesnell, 1999) and Mars show similar properties. Jupiter model results (Kim et al, 2000), which is a complete ionosphere model, sampled at a predawn local time, predicts metallic ions to be dominant below the main ion layer.…”

mentioning

confidence: 99%