The loss of atmosphere from Mars.

Luhmann et al. (1) and Jakosky et al. (2) showed that the Martian atmosphere was eroded (sputtered) by energetic O ions that are formed from escaping 0 and accelerated back into the atmosphere by the solar wind fields. This collisional ejection process appears to explain measured isotope ratios for Ar and N in the martian atmosphere (2, 3) and it may affect the early evolution of this atmosphere (1-3). More recently, D. M. Kass and Y. L. Yung (4) presented a more detailed calculation of the loss of Martian atmosphere. They found that 3 bars of CO2 are driven off by sputtering, an amount three times greater than the size of Earth's atmosphere. This is a huge increase in atmospheric loss over the earlier estimate of about 0.1 bars (1, 2). This increase came about because Kass and