Biology
Scientific paper
Oct 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007asbio...7..783y&link_type=abstract
Astrobiology, Volume 7, Issue 5, pp. 783-800.
Biology
5
O/H Ratio-Atmospheric Escape, Planetary Evolution, Ionosphere, Euv/Fuv-Solar Wind
Scientific paper
We have synthesized current understanding, mainly observations, with regard to ion escape mechanisms to space from the ionosphere and exosphere of Titan and Earth-type planets, with the intent to provide an improved input for models of atmospheric evolution on early Earth and Earth-type planets and exoplanets. We focus on the role of the ionosphere and its non-linear response to solar parameters, all of which have been underestimated in current models of ancient atmospheric escape (4 billion years ago). Factors that have been overlooked include the following: (1) Much larger variation of O+ outflow than H+ outflow from the terrestrial ionosphere, depending on solar and geomagnetic activities (an important consideration when attempting to determine the oxidized state of the atmosphere of early Earth); (2) magnetization of the ionopause, which keeps ionospheric ions from escaping and controls many other escape processes; (3) extra ionization by, for example, the critical ionization velocity mechanism, which expands the ionosphere to greater altitudes than current models predict; and (4) the large escape of cold ions from the dense, expanded ionosphere of Titan. Here we offer, as a guideline for quantitative simulations, a qualitative diagnosis of increases or decreases of non-thermal escape related to the ionosphere for magnetized and unmagnetized planets in response to changes in solar parameters (i.e., solar EUV/FUV flux, solar wind dynamic pressure, and interplanetary magnetic field).
Wahlund Jan-Erik
Yamauchi Masatoshi
No associations
LandOfFree
Role of the Ionosphere for the Atmospheric Evolution of Planets does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Role of the Ionosphere for the Atmospheric Evolution of Planets, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Role of the Ionosphere for the Atmospheric Evolution of Planets will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-951932