PDS: The Planetary Atmospheres NodePlanetary Atmospheres
Cover Page/Proposal Summary
ROSS-00 NRA 00-OSS-01
Date Due: 4/28/2000
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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: Tenuous Atmospheres |
| Major Equipment Proposal? No |
| Do you intend to submit an Education/Public Outreach (E/PO) proposal? No |
| Proposal Title: |
| Atmospheric Loss Processes at Io |
| Abbreviated Proposal Title: |
| Atmospheric Loss Processes at Io |
| Principal Investigator: |
| Dr. Barry Mauk Applied Physics Laboratory 7-366 Johns Hopkins University 11100 Johns Hopkins Road of Route 29 Laurel, MD 20723 Phone: 240-228-6023 Fax: 240-228-6670 E-mail: barry.mauk@jhuapl.edu |
| Signature | Date |
| _____________________________________ | ____________ |
| Co-Investigators and Collaborators: | |||
| Type | Name | Affiliation | |
| Sci Co-I | Dr. Christopher P Paranicas | Johns Hopkins APL | Chris.Paranicas@jhuapl.edu |
| Sci Co-I | Dr. Robert B Decker | Johns Hopkins APL | Robert.Decker@jhuapl.edu |
Proposal Summary:
Energetic charged particles measured by the Galileo and Voyager spacecraft are probes of the neutral gas density in the vicinity of the satellite Io and its torus. Analysis of these data reveals deep decreases in charged particle intensity in the vicinity of the equatorial neutral gas clouds. Energetic charged particles are lost via charge exchange with ambient neutrals during their multiple excursions around Jupiter. They are therefore diagnostic of the longitudinally-averaged densities of the extended gas clouds produced by Io. In addition to sampling the neutral cloud, charged particles also help populate it. Corotating plasma ions liberate neutrals near Io's exobase in so-called knock-on collisions and energetic charged particles collide with Io's surface, sputtering molecules into its atmosphere. Recent analyses of these data suggest that densities and distributions of the extended neutral clouds near Io's orbit are highly time-variable. This is a curious phenomenon which impacts the volcanic sources of gas, its escape into circumplanetary orbits, and its lifetime against loss and transport. We propose to use multiple data sets, including those from Galileo and Voyager, to study the closely coupled space-environment/Io-atmosphere system. Our principal goal is to understand why the steady-state neutral gas environment near Io is so variable. To answer this question we will assess those processes by which Io and its atmosphere variably sheds atmospheric neutrals and the processes by which the gases are transported and redistributed away from Io. A product of this activity will be the observed and modeled spatial distributions of neutral gas in the vicinity of Io and its torus.
Certification of Compliance with Applicable Executive Orders and U.S. Code
By submitting the proposal identified in this Cover Sheet/Proposal Summary in response to this NRA or AO, the Authorizing Official of the proposing institution (or the individual proposer if there is no proposing institution) as identified below:
Willful provision of false information in this proposal and/or its supporting documents, or in reports required under an ensuing award, is a criminal offense (U.S. Code, Title 18, Section 1001).
