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Constantly forming sporadic E-like layers and rifts in the Martian ionosphere and their implications for Earth

Abstract

Understanding and predicting processes that perturb planetary ionospheres is of paramount importance for long-distance radio communication. Perhaps the oldest known ionospheric disturbances are ‘sporadic E layers’1: unpredictable and short-lived concentrations of plasma2, which can bounce radio signals over the horizon for thousands of kilometres3. Consequentially, local radio broadcasts can become jammed by more distant transmissions, and thus sporadic E layers are a potentially serious complication for commercial radio, aviation, shipping or the military. According to the current theory of their formation, we should also expect an equal proportion of localized ionospheric density depletions to develop. However, no such ‘sporadic E rifts’ have been detected in over 85 years of ionospheric research. In addition, despite being common at Earth, no sporadic E layers have yet been reported at other planets. Here we report the detection of sporadic E-like phenomena in the ionosphere of Mars by NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, providing a physical explanation for previous unexplained observations at Mars4,5,6,7. We observe enhanced-density layers that can be explained through the presence of a sporadic E-like mechanism, and we establish the existence of sporadic E rifts in nature. We find that, unlike the case at Earth, Martian sporadic E features are trapped in a near-perpetual state of dynamic formation and may form at predictable locations. Also unlike the case at Earth, Martian sporadic E features are readily accessible to satellites, and indeed MAVEN has already encountered more of the phenomena at Mars than have ever been explored in situ at Earth with suborbital rockets.

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Fig. 1: Formation of sporadic E layers at Earth.
Fig. 2: In situ MAVEN observations at a sporadic E-like layer and rift at Mars.
Fig. 3: Map of sporadic E-like events at Mars encountered by MAVEN.
Fig. 4: Ion lifetime at Mars.

Data availability

MAVEN data are available from the Planetary Plasma Interactions Node of the NASA Planetary Data System (https://pds-ppi.igpp.ucla.edu/).

Code availability

Software to analyse data from the MAVEN Particles and Fields package is available through the MAVEN Science Data Center (https://lasp.colorado.edu/maven/sdc/public/), and through the University of California at Berkeley’s Space Science Laboratory TPLOT package (http://sprg.ssl.berkeley.edu/data/maven/misc/socware/).

References

  1. 1.

    Appleton, E. V. On two methods of ionospheric investigation. Proc. Phys. Soc. 45, 673–688 (1933).

    ADS  Article  Google Scholar 

  2. 2.

    Pfaff, R. F. The near-Earth plasma environment. Space Sci. Rev. 168, 23–112 (2012).

  3. 3.

    Dellinger, J. H. The role of the ionosphere in radio wave propagation. Trans. Am. Inst. Electr. Eng. 58, 803–822 (1939).

    Article  Google Scholar 

  4. 4.

    Withers, P., Mendillo, M., Risbeth, H., Hinson, D. P. & Arkani-Hamed, J. Ionospheric characteristics above Martian crustal magnetic anomalies. Geophys. Res. Lett. 32, L16204 (2005).

    ADS  Article  Google Scholar 

  5. 5.

    Bougher, S. et al. Early MAVEN Deep Dip campaign reveals thermosphere and ionosphere variability. Science 350, aad0459 (2015).

  6. 6.

    Grebowsky, J. M. et al. Unique, non-Earthlike, meteoritic ion behavior in upper atmosphere of Mars. Geophys. Res. Lett. 44, 3066–3072 (2017).

    ADS  Article  Google Scholar 

  7. 7.

    Mayyasi, M., Withers, P. & Fallows, K. A sporadic topside layer in the ionosphere of Mars from analysis of MGS radio occultation data. J. Geophys. Res. Space Phys. 123, 883–900 (2017).

    ADS  Article  Google Scholar 

  8. 8.

    Whitehead, J. D. The formation of the sporadic E layer in the temperate zones. J. Atmos. Terr. Phys. 20, 49–58 (1961).

    ADS  Article  Google Scholar 

  9. 9.

    Hines, C. O. The formation of midlatitude sporadic E layers. J. Geophys. Res. 69, 1018–1019 (1964).

    ADS  Article  Google Scholar 

  10. 10.

    Whitehead, J. D. Production and prediction of sporadic E. Rev. Geophys. 8, 65–144 (1970).

    ADS  Article  Google Scholar 

  11. 11.

    McFadden, J. P. et al. MAVEN SupraThermal and Thermal Ion Composition (STATIC) instrument. Space Sci. Rev. 195, 199–256 (2015).

    ADS  Article  Google Scholar 

  12. 12.

    Mahaffy, P. R. et al. The Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution Mission. Space Sci. Rev. 195, 49–73 (2015).

    ADS  Article  Google Scholar 

  13. 13.

    Andersson, L. et al. The Langmuir Probe and Waves (LPW) Instrument for MAVEN. Space Sci. Rev. 195, 173–198 (2015).

    ADS  Article  Google Scholar 

  14. 14.

    Seddon, C. J. in AGARDograph 34: Sporadic E Ionization (ed. Landmark, B.) 171–182 (NATO Advisory Group for Aeronautical Research and Development, 1958).

  15. 15.

    Grebowsky, J. M. & Aikin, A. C. in Meteors in the Earth’s Atmosphere (Einaudi, F.) 189–214 (Cambridge University Press, 2002).

  16. 16.

    Earle, G. D., Kane, T. J., Pfaff, R. F. & Bounds, S. R. Ion layer separation and equilibrium zonal winds in midlatitude sporadic E. Geophys. Res. Lett. 27, 461–464 (2000).

    ADS  Article  Google Scholar 

  17. 17.

    Connerney, J. E. P. et al. Magnetic lineations in the ancient crust of Mars. Science 284, 794–798 (1999).

    ADS  Article  Google Scholar 

  18. 18.

    Mitchell, D. L. et al. The MAVEN Solar Wind Electron Analyzer. Space Sci. Rev. 200, 495–528 (2016).

    ADS  Article  Google Scholar 

  19. 19.

    Pätzold, M. et al. A sporadic third layer in the ionosphere of Mars. Science 310, 837–839 (2005).

    ADS  Article  Google Scholar 

  20. 20.

    Crismani, M. M. J. et al. Localized ionization hypothesis for transient ionospheric layers. J. Geophys. Res. Space Phys. 124, 4870–4880 (2019).

    ADS  Article  Google Scholar 

  21. 21.

    Shinagawa, H. & Cravens, T. E. The ionospheric effects of a weak intrinsic magnetic field at Mars. J. Geophys. Res. 97, 1027–1035 (1992).

    ADS  Article  Google Scholar 

  22. 22.

    Riousset, J. A. et al. Electrodynamics of the Martian dynamo region near magnetic cusps and loops. Geophys. Res. Lett. 41, 1119–1125 (2014).

    ADS  Article  Google Scholar 

  23. 23.

    Glatzmaier, G. A. & Roberts, P. H. A three-dimensional self-consistent computer simulation of a geomagnetic field reversal. Nature 377, 203–209 (1995).

    ADS  Article  Google Scholar 

  24. 24.

    Roddy, P. A., Earle, G. D., Swenson, C. M., Carlson, C. G. & Bullett, T. W. Relative concentrations of molecular and metallic ions in midlatitude intermediate and sporadic E layers. Geophys. Res. Lett. 31, L19807 (2004).

    ADS  Article  Google Scholar 

  25. 25.

    Haldoupis, C., Pancheva, D., Singer, W., Meek, C. & MacDougall, J. An explanation for the seasonal dependence of midlatitude sporadic E layers. J. Geophys. Res. 112, A06315 (2007).

    ADS  Article  Google Scholar 

  26. 26.

    Didebulidze, G. G. & Lomidze, L. N. The formation of sporadic E layers by a vortical perturbation excited in a horizontal wind shear flow. Ann. Geophys. 26, 1741–1749 (2008).

    ADS  Article  Google Scholar 

  27. 27.

    Smith, L. G. & Mechtly, E. A. Rocket observations of sporadic E layers. Radio Sci. 7, 367–376 (1972).

    ADS  Article  Google Scholar 

  28. 28.

    Collinson, G. et al. Traveling ionospheric disturbances at Mars. Geophys. Res. Lett. 46, 4554–4563 (2019).

    ADS  Article  Google Scholar 

  29. 29.

    Connerney, J. E. P. et al. The MAVEN magnetic field investigation. Space Sci. Rev. 195, 257–291 (2015).

  30. 30.

    Schunk, R. and Nagy, A. F. Ionospheres: Physics, Plasma Physics, and Chemistry Cambridge Atmospheric and Space Science Series, 2nd edn (Cambridge University Press, 2009).

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Acknowledgements

This work was supported by the MAVEN mission. We thank C. Fowler for assistance in differentiating Martian sporadic E features from Martian ionospheric irregularities. We also thank A.P. McCall of the Kunyung Institute for Space Physics, Melbourne, Australia, for useful discussions.

Author information

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Contributions

G.A.C. analysed the data and wrote the paper. J.G. contributed the explanation for the fundamental physical mechanism at play. J.M., D.M., M.B., J.E. and B.J. conceived and designed the experiment. P.W. and M.F.V. compared our in situ results with remote previous sensing observations. R.L. analysed the data.

Corresponding author

Correspondence to Glyn A. Collinson.

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The authors declare no competing interests.

Additional information

Peer review information Nature Astronomy thanks Michael Pezzopane, Hiroyuki Shinagawa and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Comparison of plasma density vs. altitude of Sporadic E at Mars and Earth.

Comparison of observations of Sporadic-E-like features at Mars (red) and Earth (green). Each panel shows plasma density (cm-3) versus altitude (km). Top panels show observations of ion density (each species colour coded), Bottom panels show electron densities. Panels a,b.) MAVEN in situ observations (Fig. 2, main paper); Panels c,d.) remote-sensing observations by the Mars Global Surveyor (MGS); Panels e,f.) In situ observations of Sporadic E at Earth by suborbital rocketcraft. Consistent with previous remote-sensing results from Mars and at Earth, Martian Sporadic E appear to be narrow structures only a few kilometres across.

Extended Data Fig. 2 Expanded MAVEN data plots.

Expanded plot of additional supporting MAVEN data from our two prime events.

Supplementary information

Supplementary Information

Supplementary discussion, Tables 1 and 2 and Fig. 1.

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Collinson, G.A., McFadden, J., Grebowsky, J. et al. Constantly forming sporadic E-like layers and rifts in the Martian ionosphere and their implications for Earth. Nat Astron 4, 486–491 (2020). https://doi.org/10.1038/s41550-019-0984-8

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