The newly detected oxygen atmosphere of Europa is modeled by invoking charged particle sputtering with H2O and O2 molecules as the main ejecta. The magnetospheric corotating ions could provide the required source strength (∼3 × 1026 sec-1) of O2 molecules if a fraction (∼20%) of the exospheric ions were recycled to Europa's surface where they produce additional sputtering product. Two exospheric components are expected to form: an extended corona with a size of a few satellite radii which is composed of sputtered molecules in ballistic motion, and a thermal population with a surface density of 108-109 cm-3 and a scale height of about 20 km. The electron impact ionization of this exosphere would lead to an Io-like interaction with the jovian magnetosphere with a field-aligned Birkeland current of about 5 × 105 A.
|Number of pages||9|
|State||Published - Apr 1996|