Journal article
The Penetration of Draped Magnetic Field Into the Martian Upper Ionosphere and Correlations With Upstream Solar Wind Dynamic Pressure
Journal of geophysical research. Space physics, Vol.124(4), pp.3021-3035
04/2019
DOI: 10.1029/2019JA026550
Abstract
Open and draped magnetic field topologies are important at Mars because they can provide ionospheric particles a path to escape to space. Four years of Mars Atmosphere and Volatile EvolutioN data are analyzed in this study, demonstrating that the altitude at which the ionospheric density drops below 10(2) cm(-3) is essentially coincident with the altitude down to which open and draped magnetic field lines are observed in the ionosphere. During times of enhanced solar wind dynamic pressure, a greater fraction of the magnetic topology was observed as open or draped (as opposed to closed) above densities of 10(2) cm(-3). The altitudes at which the ionospheric density fell below 10(2) cm(-3), and the magnetic field topology transitioned from closed to open or draped, also decreased during higher dynamic pressure conditions. Times of enhanced solar wind dynamic pressure thus appear to drive greater penetration of draped magnetic field into the ionosphere, enhancing the rate of reconnection between draped and crustal magnetic fields and producing more open field. Such observations may have implications for the long-term evolution of the Martian ionosphere; the historic solar wind is thought to have been denser and faster than present-day conditions, and "quiet time" conditions may have been equivalent to extreme dynamic pressure events today. Depending on past atmospheric conditions at Mars, draped topology may have routinely penetrated deep into the ionosphere, and quiet time rates of ionospheric escape to space may thus have been much greater for early Mars than today.
Details
- Title: Subtitle
- The Penetration of Draped Magnetic Field Into the Martian Upper Ionosphere and Correlations With Upstream Solar Wind Dynamic Pressure
- Creators
- C. M. Fowler - University of California, BerkeleyC. O. Lee - Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USAS. Xu - Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USAD. L. Mitchell - Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USAR. Lillis - University of California, BerkeleyT. Weber - Laboratory for Atmospheric and Space PhysicsJ. Halekas - University of IowaL. Andersson - Laboratory for Atmospheric and Space PhysicsJ. Espley - Goddard Space Flight CenterR. E. Ergun - University of Colorado BoulderC. Mazelle - Université de ToulouseJ. Luhmann - University of California, Berkeley
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.124(4), pp.3021-3035
- DOI
- 10.1029/2019JA026550
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Publisher
- Amer Geophysical Union
- Number of pages
- 15
- Grant note
- NNH10CC04C / NASA through the Mars Exploration Program
- Language
- English
- Date published
- 04/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428767302771
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