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Hanley KG, McFadden JP, Mitchell DL, Fowler CM, Stone SW, Yelle RV, Mayyasi M, Ergun RE, Andersson L, Benna M, Elrod MK, Jakosky BM. In Situ Measurements of Thermal Ion Temperature in the Martian Ionosphere. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2021; 126:e2021JA029531. [PMID: 35865356 PMCID: PMC9286691 DOI: 10.1029/2021ja029531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 10/22/2021] [Accepted: 11/19/2021] [Indexed: 06/15/2023]
Abstract
In situ measurements of ionospheric and thermospheric temperatures are experimentally challenging because orbiting spacecraft typically travel supersonically with respect to the cold gas and plasma. We present O 2 + temperatures in Mars' ionosphere derived from data measured by the SupraThermal And Thermal Ion Composition instrument onboard the Mars Atmosphere and Volatile EvolutioN spacecraft. We focus on data obtained during nine special orbit maneuvers known as Deep Dips, during which MAVEN lowered its periapsis altitude from the nominal 150 to 120 km for 1 week in order to sample the ionospheric main peak and approach the homopause. We use two independent techniques to calculate ion temperatures from the measured energy and angular widths of the supersonic ram ion beam. After correcting for background and instrument response, we are able to measure ion temperatures as low as 100 K with associated uncertainties as low as 10%. It is theoretically expected that ion temperatures will converge to the neutral temperature at altitudes below the exobase region (∼180-200 km) due to strong collisional coupling; however, no evidence of the expected thermalization is observed. We have eliminated several possible explanations for the observed temperature difference between ions and neutrals, including Coulomb collisions with electrons, Joule heating, and heating caused by interactions with the spacecraft. The source of the energy maintaining the high ion temperatures remains unclear, suggesting that a fundamental piece of physics is missing from existing models of the Martian ionosphere.
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Affiliation(s)
- K. G. Hanley
- Space Sciences LaboratoryUniversity of California BerkeleyBerkeleyCAUSA
| | - J. P. McFadden
- Space Sciences LaboratoryUniversity of California BerkeleyBerkeleyCAUSA
| | - D. L. Mitchell
- Space Sciences LaboratoryUniversity of California BerkeleyBerkeleyCAUSA
| | - C. M. Fowler
- Space Sciences LaboratoryUniversity of California BerkeleyBerkeleyCAUSA
- Department of Physics and AstronomyWest Virginia UniversityMorgantownWVUSA
| | - S. W. Stone
- Lunar and Planetary LaboratoryUniversity of ArizonaTucsonAZUSA
| | - R. V. Yelle
- Lunar and Planetary LaboratoryUniversity of ArizonaTucsonAZUSA
| | - M. Mayyasi
- Astronomy DepartmentBoston UniversityBostonMAUSA
| | - R. E. Ergun
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | - L. Andersson
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | - M. Benna
- Center for Research and Exploration in Space Science and TechnologyNASA Goddard Space Flight CenterGreenbeltMDUSA
- University of MarylandBaltimore CountyMDUSA
| | - M. K. Elrod
- Center for Research and Exploration in Space Science and TechnologyNASA Goddard Space Flight CenterGreenbeltMDUSA
- University of MarylandCollege ParkMDUSA
| | - B. M. Jakosky
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
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Huestis DL, Slanger TG, Sharpee BD, Fox JL. Chemical origins of the Mars ultraviolet dayglow. Faraday Discuss 2010; 147:307-22; discussion 379-403. [DOI: 10.1039/c003456h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Thomas RD. When electrons meet molecular ions and what happens next: dissociative recombination from interstellar molecular clouds to internal combustion engines. MASS SPECTROMETRY REVIEWS 2008; 27:485-530. [PMID: 18618616 DOI: 10.1002/mas.20169] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The interaction of matter with its environment is the driving force behind the evolution of 99% of the observed matter in the universe. The majority of the visible universe exists in a state of weak ionization, the so called fourth state of matter: plasma. Plasmas are ubiquitous, from those occurring naturally; interstellar molecular clouds, cometary comae, circumstellar shells, to those which are anthropic in origin; flames, combustion engines and fusion reactors. The evolution of these plasmas is driven by the interaction of the plasma constituents, the ions, and the electrons. One of the most important subsets of these reactions is electron-molecular ion recombination. This process is significant for two very important reasons. It is an ionization reducing reaction, removing two ionised species and producing neutral products. Furthermore, these products may themselves be reactive radical species which can then further drive the evolution of the plasma. The rate at which the electron reacts with the ion depends on many parameters, for examples the collision energy, the internal energy of the ion, and the structure of the ion itself. Measuring these properties together with the manner in which the system breaks up is therefore critical if the evolution of the environment is to be understood at all. Several techniques have been developed to study just such reactions to obtain the necessary information on the parameters. In this paper the focus will be on one the most recently developed of these, the Ion Storage Ring, together with the detection tools and techniques used to extract the necessary information from the reaction.
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Affiliation(s)
- Richard D Thomas
- Department of Physics, Albanova University Centre, Stockholm University, S106 91 Stockholm, Sweden.
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Petrignani A, Hellberg F, Thomas RD, Larsson M, Cosby PC, Zande WJVD. Vibrational dependence in the dissociative recombination of O2+. ACTA ACUST UNITED AC 2005. [DOI: 10.1088/1742-6596/4/1/025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Petrignani A, van der Zande WJ, Cosby PC, Hellberg F, Thomas RD, Larsson M. Vibrationally resolved rate coefficients and branching fractions in the dissociative recombination of O2+. J Chem Phys 2005; 122:14302. [PMID: 15638654 DOI: 10.1063/1.1825991] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have studied the dissociative recombination of the first three vibrational levels of O(2) (+) in its electronic ground X (2)Pi(g) state. Absolute rate coefficients, cross sections, quantum yields and branching fractions have been determined in a merged-beam experiment in the heavy-ion storage ring, CRYRING, employing fragment imaging for the reaction dynamics. We present the absolute total rate coefficients as function of collision energies up to 0.4 eV for five different vibrational populations of the ion beam, as well as the partial (vibrationally resolved) rate coefficients and the branching fractions near 0 eV collision energy for the vibrational levels v=0, 1, and 2. The vibrational populations used were produced in a modified electron impact ion source, which has been calibrated using Cs-O(2)(+) dissociative charge transfer reactions. The measurements indicate that at low collision energies, the total rate coefficient is weakly dependent on the vibrational excitation. The calculated thermal rate coefficient at 300 K decreases upon vibrational excitation. The partial rate coefficients as well as the partial branching fractions are found to be strongly dependent on the vibrational level. The partial rate coefficient is the fastest for v=0 and goes down by a factor of two or more for v=1 and 2. The O((1)S) quantum yield, linked to the green airglow, increases strongly upon increasing vibrational level. The effects of the dissociative recombination reactions and super elastic collisions on the vibrational populations are discussed.
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Affiliation(s)
- Annemieke Petrignani
- FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
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Alcaraz C, Nicolas C, Thissen R, Zabka J, Dutuit O. 15N+ + CD4 and O+ + 13CO2 State-Selected Ion−Molecule Reactions Relevant to the Chemistry of Planetary Ionospheres. J Phys Chem A 2004. [DOI: 10.1021/jp0477755] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christian Alcaraz
- LURE, UMR 130, Bât. 209D, Centre Universitaire Paris-Sud, 91898 Orsay Cedex, Laboratoire de Chimie Physique, UMR 8000, Bât. 350, Centre Universitaire Paris-Sud, 91405 Orsay, France, and J. Heyrovsky Institute of Physical Chemistry, Dolejskova 3, CZ 18223 Praha 8 - Kobylisy, Czech Republic
| | - Christophe Nicolas
- LURE, UMR 130, Bât. 209D, Centre Universitaire Paris-Sud, 91898 Orsay Cedex, Laboratoire de Chimie Physique, UMR 8000, Bât. 350, Centre Universitaire Paris-Sud, 91405 Orsay, France, and J. Heyrovsky Institute of Physical Chemistry, Dolejskova 3, CZ 18223 Praha 8 - Kobylisy, Czech Republic
| | - Roland Thissen
- LURE, UMR 130, Bât. 209D, Centre Universitaire Paris-Sud, 91898 Orsay Cedex, Laboratoire de Chimie Physique, UMR 8000, Bât. 350, Centre Universitaire Paris-Sud, 91405 Orsay, France, and J. Heyrovsky Institute of Physical Chemistry, Dolejskova 3, CZ 18223 Praha 8 - Kobylisy, Czech Republic
| | - Jan Zabka
- LURE, UMR 130, Bât. 209D, Centre Universitaire Paris-Sud, 91898 Orsay Cedex, Laboratoire de Chimie Physique, UMR 8000, Bât. 350, Centre Universitaire Paris-Sud, 91405 Orsay, France, and J. Heyrovsky Institute of Physical Chemistry, Dolejskova 3, CZ 18223 Praha 8 - Kobylisy, Czech Republic
| | - Odile Dutuit
- LURE, UMR 130, Bât. 209D, Centre Universitaire Paris-Sud, 91898 Orsay Cedex, Laboratoire de Chimie Physique, UMR 8000, Bât. 350, Centre Universitaire Paris-Sud, 91405 Orsay, France, and J. Heyrovsky Institute of Physical Chemistry, Dolejskova 3, CZ 18223 Praha 8 - Kobylisy, Czech Republic
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