Cover Page/Proposal Summary
ROSS-99 NRA 99-OSS-01
Date Due: 5/3/99
This proposal shall be used and disclosed for evaluation purposes only, and a copy of this Government notice shall be applied to any reproduction or abstract thereof. Any authorized restrictive notices that the submitter places on this proposal shall also be strictly complied with. Disclosure of this proposal for any reason outside the Government evaluation purposes shall be made only to the extent authorized by the Government. |
Proposal Type: New Proposal |
Proposal Category: Laboratory |
Major Equipment Proposal? No |
Do you intend to submit an Education/Public Outreach (E/PO) proposal? No |
Proposal Title: |
UV Emission Processes in Planetary Atmospheres by Electron Impact |
Abbreviated Proposal Title: |
UV Emission Processes by Electron Impact |
Principal Investigator: |
Dr. Joseph M.
Ajello UV Emission Processes Team Space Sciences Division MS 183-601 JPL 4800 Oak Grove Drive Pasadena, CA 91109-8099 Phone: 818-354-2457 Fax: 818-393-4605 E-mail: jajello@jpluvs.jpl.nasa.gov |
Signature | Date |
_____________________________________ | ____________ |
Co-Investigators and Collaborators: | |||
Type | Name | Affiliation | |
Sci Co-I | Dr. Geoffrey K. James | JPL | gkjames@pop.jpl.na sa.gov |
Sci Co-I | Prof. Donald E. Shemansky | USC | dons@hippolyta .usc.edu |
Sci Co-I | Dr. Xianming Liu | USC | xliu@jpluvs.jpl.nasa .gov |
Sci Collab | Dr. John T. Clarke | Univ. Michigan | clarke@sunshine.sprl.umich.edu |
Sci Collab | Dr. Herve Abgrall | Meudon Observatory | abgrall@mesioq.obspm.fr |
Sci Collab | Dr. Alex Dalgarno | Harvard | dalgarno@cf a.harvard.edu |
Proposal Summary:
Analysis of observations of planetary atmospheres by Hubble Space Telescope, Galileo, Cassini and FUSE require laboratory measurements of collision cross sections. A dominant mechanisim for energy transfer in the upper atmosphere occurs through electron collision processes with neutral species. In response to the need for accurate collision cross sections JPL established UV instrumentation to routinely measure emission cross sections of gases. In this program we concentrate on the species H2, N2, O, O2 and H the most important species of the upper atmospheres of the Jovian Planetary Systems. The objectives are :1) to measure electron impact cross sections (0-2keV) and fluorescence spectra (50-400 nm)and 2) to develop analytic collision strengths for electron energy loss codes. Cross sections are needed to model spectroscopic observations of jovian and terrestrial planets in preflight instrument calibration, data analysis and mission planning phases. UV emission cross sections can not be established by theory due to the high density of perturbing states. JPL has established three unique UV instruments, including a high resolution spectrometer with resolving power of 60000, to study electron impact fluorescence. The rotationally resolved UV spectrum of H2 Rydberg bands (B,B',B",C,D,D')will be compared to theory. The H2 atlas will be updated with new rotational lines and Rydberg states. A pulsed gun technique allows separation of cascade (slow) and direct (fast) electron excitation processes. UV Lyman band observations are used to determine global energy input to the atmosphere. The H2 EF->B->X (cascade) and B->X (direct) excitation cross sections, which comprise the Lyman Band system can be separately measured. Atomic O and H radical source high density beams established for cross section studies of resonance lines: OI(130.4nm), H(102.5nm) and cascade (visble). N2 states (b,b',c,c',o) will be studied to determine rovibronic predissociation yields.