Modeling Spectra of the North and South Jovian X-ray Auroras

Journal Article · Fri Aug 01 04:00:00 EDT 2008 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/2008JA013062· OSTI ID:936810

Kharchenko, Vasili A ^[1]; Bhardwaj, Anil ^[2]; Dalgarno, A ^[3]; Schultz, David Robert ^[1]; Stancil, Phillip C ^[4]

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1. ORNL
2. Vikram Sarabhai Space Center, Trivandrum, India
3. Harvard-Smithsonian Center for Astrophysics
4. University of Georgia

Spectra of Jovian X-ray auroras observed from the North and South poles with the Chandra X-ray telescope are analyzed and compared with predicted spectra of the charge-exchange mechanism. To determine the theoretical spectra of Jovian X-ray auroras, we model numerically the collisionally induced evolution of energy and charge distributions of Oq+ and Sq+ ions, precipitating into the Jovian atmosphere. Monte Carlo simulations of the energy and charge relaxation of the precipitating ions are carried out with updated cross-sections of the ion stripping, electron capture, and gas-ionization collisions. X-ray and Extreme Ultraviolet (EUV) spectra of cascading radiation induced by individual energetic sulfur and oxygen ions are calculated, and relative intensities of X-ray emission lines are determined. Synthetic spectra of X-ray and EUV photons are computed at different initial kinetic energies and compositions of ion-precipitating fluxes. Theoretical spectra with adjustable initial energies and relative fraction of sulfur and oxygen ions are shown to be in good agreement with the spectra of X rays detected from the South and North polar regions. The abundances and initial energies of the precipitating ions are inferred by comparing synthetic and observed X-ray spectra. Comparisons are performed independently for the North and South pole emissions. Abundances of the precipitating sulfur ions are found to be four to five times smaller than those of oxygen ions, and averaged ion energies are determined to lie between 1 and 2 MeV/amu. Slightly different ion flux compositions are found to describe the observed spectra of X-ray emission from the North and South poles.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: ORNL work for others
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 936810
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Vol. 113
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
74 ATOMIC AND MOLECULAR PHYSICS
CHARGE DISTRIBUTION
CHARGE EXCHANGE
CROSS SECTIONS
ELECTRON CAPTURE
KINETICS
OXYGEN IONS
PHOTONS
POLAR REGIONS
RADIATIONS
RELAXATION
SPECTRA
SULFUR
SULFUR IONS
TELESCOPES
X-RAY SPECTRA