Physics
Scientific paper
Dec 2003
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003agufm.p32a1069c&link_type=abstract
American Geophysical Union, Fall Meeting 2003, abstract #P32A-1069
Physics
2459 Planetary Ionospheres (5435, 5729, 6026, 6027, 6028), 2481 Topside Ionosphere, 2499 General Or Miscellaneous, 5435 Ionospheres (2459), 6225 Mars
Scientific paper
The Electron Reflectometer on Mars Global Surveyor measured the energy/angle distributions of 10 eV to 20 keV electrons at altitudes from 170 km to > 17,000 km during aerobraking. Two low-altitude plasma regimes were identified, separated by a highly variable but persistent boundary called the photoelectron boundary, or PEB. Below the PEB, the energy spectra are dominated by ionospheric photoelectrons, and we observe the shapes of these spectra to change systematically with altitude and solar zenith angle (SZA). For 85 o < SZA < 95 o, the 10 eV - 100 eV spectrum changes significantly from 170 km to 230 km, above which there are no further changes. At lower solar zenith angles (65 o - 75 o), these changes occur over a larger altitude range (170 km - 260 km). The 100 eV - 1000 eV spectrum changes significantly from 170 to 210 km, independent of solar zenith angle. The altitude range over which spectral changes are observed is close to the exobase, where collisions with atmospheric neutrals become important. Spectral changes likely result as the spacecraft approaches the exobase and the volume of ionosphere sampled by a given electron spectrum extends to lower altitudes, where collisions and compositional variations can modify photoelectron energies. When the spacecraft is well above the exobase, the volume of ionosphere sampled is independent of altitude, and the photoelectron spectrum is constant.
Chou Shu-Hsien
Lin Robert P.
Mitchell David Leroy
No associations
LandOfFree
Characterizing Primary Photoelectrons in Mars' Ionosphere 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 Characterizing Primary Photoelectrons in Mars' Ionosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Characterizing Primary Photoelectrons in Mars' Ionosphere will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1425469