Cross Sections for Emission of Lyman-Alpha Radiation in Collisions of 1-25 keV Protons and Hydrogen Atoms with Constituents of Planetary Atmospheres.
Abstract
Cross sections are reported for emission of Lyman-alpha radiation in collisions of a charge-equilibrated 1-25 keV hydrogen beam with N2, O2, CO, CO2, NH3, CH4, and H2. For each target molecule, the separate cross sections for formation of H(2p) and H(2s) in H(+) and H collisions and the fractional population of these projectiles in a charge-equilibrated beam are used to calculate the effective cross section for formation of H(2p) and H(2s). Individual contributions to the overall Lyman-alpha intensity owing to projectile and dissociative excitation are presented for the hydrogen-containing compounds. The results show that, for both projectile and dissociative excitation, collisions involving impact of fast hydrogen atoms rather than protons are the major source of Lyman-alpha production in an aurora. Projectile excitation is demonstrated to be a substantially more important source of Lyman alpha than dissociative excitation in the 1-25 keV energy range. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 31, 1972
- Accession Number
- AD0739184
Entities
People
- John H. Birely
- Robert J. McNeal
Organizations
- The Aerospace Corporation