Document Type

Article

Publication Date

1992

Abstract

Observations of the H3+ infrared emission at 2 and 4 μm have suggested that H3+ is in local thermodynamic equilibrium (LTE) in the region of the Jovian ionosphere from which the emissions originate. We have tested this assumption by calculating the vibrational distribution of H3+ over the altitude range of 350 to 1500 km above the methane cloud tops (1 to 4 × 10−3 μbar). We have constructed a model of the Jovian auroral ionosphere in which the neutral temperatures are enhanced over those of the mid-latitude ionosphere, as suggested by observations and models of the auroral region. We have modeled the precipitation of 10-keV electrons with an energy flux of 1 erg cm−2 s−1. Both the energy and energy flux are less than those that are implicated in the production of the UV aurora. We have computed the densities and vibrational distribution of H3+ and find that the distribution of the six lowest states of H3+ can be determined fairly well in spite of uncertainties in the atomic and molecular data. Since the nearly resonant transfer of vibration from H2(υ=1) is an important process in populating the H3+1=0,υ2=2) state, it is necessary to model the vibrational distribution of H2 as well. The computed altitude profiles and vibrational distributions of H3+ and H2 are consistent with the observations of infrared emission in the 2-and 4-μm regions. The H3+ is not in LTE near and above the H3+ peak, since loss of the H3+1=0,υ2=1) and H3+1=0,υ2=2) states by radiation is approximately equal to the collisional loss rate.

Comments

Copyright © 1992 by the American Geophysical Union.

The following article appeared in the Journal of Geophysical Research: Planets 97(E4), and may be found at http://onlinelibrary.wiley.com/doi/10.1029/92JE00454/full

Permission to Deposit an Article in an Institutional Repository:

Adopted by Council 13 December 2009.

AGU allows authors to deposit their journal articles if the version is the final published citable version of record, the AGU copyright statement is clearly visible on the posting, and the posting is made 6 months after official publication by the AGU.

DOI

10.1029/92JE00454


Included in

Physics Commons

Share

COinS