Crismani, MMJ, Deigham, J, Schneider, NM et al. (5 more authors) (2019) Localized Ionization Hypothesis for Transient Ionospheric Layers. Journal of Geophysical Research: Space Physics, 124 (6). pp. 4870-4880. ISSN 2169-9402
Abstract
The persistent two‐peaked vertical structure of the Martian ionosphere is created by extreme and far ultraviolet radiation whose energies respectively determine their ionization altitude. A third low‐altitude transient layer (previously referred to as M3 or Mm) has been observed by radio occultation techniques and attributed to meteor ablation. However, recent remote sensing and in‐situ observations disfavor a meteoric origin. Here we propose an alternative hypothesis for these apparent layers associated with impact ionization from penetrating solar wind ions, previously observed as proton aurora. Localized ionization, occurring non‐globally at a given altitude range, breaks the symmetry assumed by the radio occultation technique, and creates electron layers apparently lower in the ionosphere than their true altitude. This may occur when the upstream bowshock is altered by a radial interplanetary magnetic field configuration, which allows the solar wind to penetrate directly into the thermosphere. This localized ionization hypothesis provides an explanation for apparent layers’ wide variation in heights and their transient behavior. Moreover, this hypothesis is testable with new observations by the Mars Atmospheric and Volatile EvolutioN (MAVEN) Radio Occultation Science Experiment (ROSE) in future Mars years. This hypothesis has implications for the ionospheres of Venus and Titan, where similar transient layers have been observed.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2019, American Geophysical Union. All Rights Reserved. This is the published version of the following article, 'Crismani, MMJ, Deigham, J, Schneider, NM et al (2019). Localized Ionization Hypothesis for Transient Ionospheric Layers. Journal of Geophysical Research: Space Physics'. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Ionospheres; Mars; Venus; Titan; Radio Occultation; Proton Aurora |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 03 May 2019 14:17 |
Last Modified: | 29 Oct 2019 01:39 |
Status: | Published |
Publisher: | American Geophysical Union |
Identification Number: | 10.1029/2018JA026251 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:145616 |