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ISSN  2096-3955

CN  10-1502/P

Citation: Cao, Y. T., Cui, J., Ni, B. B., Wu, X. S., Luo, Q., and He, Z. G. (2020). Bidirectional electron conic observations for photoelectrons in the Martian ionosphere. Earth Planet. Phys., 4(4), 1–5doi: 10.26464/epp2020037

doi: 10.26464/epp2020037


Bidirectional electron conic observations for photoelectrons in the Martian ionosphere


Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China


School of Astronomy and Space Sciences, University of Chinese Academy of Sciences, Beijing 100049, China


School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai, Guangdong 519082, China


Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei 230026, China


Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan 430072, China

Corresponding author: Jun Cui,

Received Date: 2020-03-28
Web Publishing Date: 2020-07-01

Electron pitch angle distributions similar to bidirectional electron conics (BECs) have been reported at Mars in previous studies based on analyses of Mars Global Surveyor measurements. BEC distribution, also termed “butterfly” distribution, presents a local minimum flux at 90° and a maximum flux before reaching the local loss cone. Previous studies have focused on 115 eV electrons that were produced mainly via solar wind electron impact ionization. Here using Solar Wind Electron Analyzer measurements made onboard the Mars Atmosphere and Volatile Evolution spacecraft, we identify 513 BEC events for 19–55 eV photoelectrons that were generated via photoionization only. Therefore, we are investigating electrons observed in regions well away from their source regions, to be distinguished from 115 eV electrons observed and produced in the same regions. We investigate the spatial distribution of the 19–55 eV BECs, revealing that they are more likely observed on the nightside as well as near strong crustal magnetic anomalies. We propose that the 19–55 eV photoelectron BECs are formed due to day-to-night transport and the magnetic mirror effect of photoelectrons moving along cross-terminator closed magnetic field lines.

Key words: Martian ionosphere; photoelectron; pitch angle distribution

Acuña, M. H., Connerney, J. E. P., Wasilewski, P., Lin, R. P., Anderson, K. A., Carlson, C. W., McFadden, J., Curtis, D. W., Réme, H., … Bauer, S. J. (1992). Mars observer magnetic fields investigation. J. Geophys. Res, 97(E5), 7799–7814.

Adams, D., Xu, S., Mitchell, D. L., Lillis, R. L., Fillingim, M., Andersson, L., Fowler, C., Connerney, J. E. P., Espley, J., and Mazelle, C. (2018). Using magnetic topology to probe the sources of Mars’ nightside ionosphere. Geophys. Res. Lett., 45(22), 12,190–12,197.

Allegrini, F., Bagenal, F., Bolton, S., Connerney, J., Clark, G., Ebert, R. W., Kim, T. K., Kurth, W. S., Levin, S., … Zink, J. L. (2017). Electron beams and loss cones in the auroral regions of Jupiter. Geophys. Res. Lett., 44(14), 7131–7139.

Bougher, S. W., Pawlowski, D., Bell, J. M., Nelli, S., McDunn, T., Murphy, J. R., Chizek, M., and Ridley, A. (2015). Mars global ionosphere–thermosphere model: solar cycle, seasonal, and diurnal variations of the mars upper atmosphere. J. Geophys. Res.: Planets, 120(2), 311–342.

Brain, D. A., Lillis, R. J., Mitchell, D. L., Halekas, J. S., and Lin, R. P. (2007). Electron pitch angle distributions as indicators of magnetic field topology near Mars. J. Geophys. Res.: Space Phys., 112(A9), A09201.

Cao, Y. T., Cui, J., Wu, X. S., Guo, J. P., and Wei, Y. (2019). Structural variability of the Nightside Martian ionosphere near the terminator: implications on plasma sources. J. Geophys. Res.: Planets, 124(6), 1495–1511.

Cao, Y. T., Cui, J., Wu, X. S., and Zhong, J. H. (2020). Photoelectron pitch angle distribution near Mars and implications on cross terminator magnetic field connectivity. Earth Planet. Phys., 4(1), 17–22.

Chen, Y., Friedel, R. H. W., Henderson, M. G., Claudepierre, S. G., Morley, S. K., and Spence, H. E. (2014). REPAD: An empirical model of pitch angle distributions for energetic electrons in the Earth’s outer radiation belt. J. Geophys. Res.: Space Phys., 119(3), 1693–1708.

Connerney, J. E. P., Espley, J., Lawton, P., Murphy, S., Odom, J., Oliversen, R., and Sheppard, D. (2015). The MAVEN magnetic field investigation. Space Sci. Rev., 195(1-4), 257–291.

Cui, J., Galand, M., Yelle, R. V., Wei, Y., and Zhang, S. J. (2015). Day-to- night transport in the Martian ionosphere: Implications from total electron content measurements. J. Geophys. Res.: Space Phys., 120(3), 2333–2346.

Duru, F., Gurnett, D. A., Morgan, D. D., Winningham, J. D., Frahm, R. A., and Nagy, A. F. (2011). Nightside ionosphere of Mars studied with local electron densities: A general overview and electron density depressions. J. Geophys. Res.: Space Phys., 116(A10), A10316.

Fox, J. L., Brannon, J. F., and Porter, H. S. (1993). Upper limits to the nightside ionosphere of Mars. Geophys. Res. Lett., 20(13), 1339–1342.

Frahm, R. A., Winningham, J. D., Sharber, J. R., Scherrer, J. R., Jeffers, S. J., Coates, A. J., Linder, D. R., Kataria, D. O., Lundin, R., … Dierker, C. (2006). Carbon dioxide photoelectron energy peaks at Mars. Icarus, 182(2), 371–382.

Garnier, P., Steckiewicz, M., Mazelle, C., Xu, S., Mitchell, D., Holmberg, M. K. G., Halekas, J. S., Andersson, L., Brain, D. A., … Jakosky, B. M. (2017). The Martian photoelectron boundary as seen by MAVEN. J. Geophys. Res.: Space Phys., 122(10), 10,472–10,485.

Girazian, Z., Mahaffy, P. R., Lillis, R. J., Benna, M., Elrod, M., and Jakosky, B. M. (2017). Nightside ionosphere of Mars: Composition, vertical structure, and variability. J. Geophys. Res.: Space Phys., 122(4), 4712–4725.

Gu, X. D., Zhao, Z. Y., Ni, B. B., Shprits, Y., and Zhou, C. (2011). Statistical analysis of pitch angle distribution of radiation belt energetic electrons near the geostationary orbit: CRRES observations. J. Geophys. Res.: Space Phys., 116(A1), A01208.

Hamil, O., Cravens, T. E., Rahmati, A., Connerney, J. E. P., and Andersson, L. (2019). Pressure gradients driving ion transport in the topside Martian atmosphere. J. Geophys. Res.: Space Phys., 124(7), 6117–6126.

Han, Q. Q., Fan, K., Cui, J., Wei, Y., Fraenz, M., Dubinin, E., Chai, L. H., Rong, Z. J., Wan, W. X., … Connerney, J. E. P. (2019). The relationship between photoelectron boundary and steep electron density gradient on Mars: MAVEN observations. J. Geophys. Res.: Space Phys., 124(10), 8015–8022.

Lundin, R., Eliasson, L., Hultqvist, B., and Stasiewicz, K. (1987). Plasma ergization on auroral field lines as observed by the Viking spacecraft. Geophys. Res. Lett., 14(4), 443–446.

Ma, Y. J., Fang, X., Nagy, A. F., Russell, C. T., and Toth, G. (2014). Martian ionospheric responses to dynamic pressure enhancements in the solar wind. J. Geophys. Res. Space Physics, 119(2), 1272–1286.

Ma, Q., Thorne, R. M., Li, W., Zhang, X. J., Mauk, B. H., Paranicas, C., Haggerty, D. K., Kurth, W. S., Connerney, J. E. P., … Bolton, S. J. (2017). Electron butterfly distributions at particular magnetic latitudes observed during Juno’s perijove pass. Geophys. Res. Lett., 44(10), 4489–4496.

Menietti, J. D., and Weimer, D. R. (1998). DE observations of electric field oscillations associated with an electron conic. J. Geophys. Res.: Space Phys., 103(A1), 431–438.

Mitchell, D. L., Lin, R. P., Mazelle, C., Rème, H., Cloutier, P. A., Connerney, J. E. P., Acuña, M.H., and Ness, N. F. (2001). Probing Mars’ crustal magnetic field and ionosphere with the MGS Electron Reflectometer. J. Geophys. Res.: Planets, 106(E10), 23,419–23,427.

Mitchell, D. L., Mazelle, C., Sauvaud, J. A., Thocaven, J. J., Rouzaud, J., Fedorov, A., Rouger, P., Toublanc, D., Taylor, E., … Jakosky, B. M. (2016). The MAVEN solar wind electron analyzer. Space Sci. Rev., 200(1-4), 495–528.

Morschhauser, A., Lesur, V., and Grott, M. (2014). A spherical harmonic model of the lithospheric magnetic field of Mars. J. Geophys. Res.: Planets, 119(6), 1162–1188.

Nagy, A. F., Winterhalter, D., Sauer, K., Cravens, T. E., Brecht, S., Mazelle, C., Crider, D., Kallio, E., Zakharov, A., …Trotignon, J. G. (2004). The plasma environment of Mars. Space Sci. Rev., 111(1-2), 33–114.

Němec, F., Morgan, D. D., Gurnett, D. A., and Duru, F. (2010). Nightside ionosphere of Mars: Radar soundings by the Mars Express spacecraft. J. Geophys. Res.: Planets, 115(E12), E12009.

Ni, B. B., Zou, Z. Y., Li, X. L., Bortnik, J., Xie, L., and Gu, X. D. (2016). Occurrence characteristics of outer zone relativistic electron butterfly distribution: a survey of Van Allen Probes REPT measurements. Geophys. Res. Lett, 43(11), 5644–5652.

Ulusen, D., Brain, D. A., and Mitchell, D. L. (2011). Observation of conical electron distributions over Martian crustal magnetic fields. J. Geophys. Res.: Space Phys., 116(A7), A07214.

Weber, T., Brain, D., Mitchell, D., Xu, S. S., Connerney, J., and Halekas, J. (2017). Characterization of low-altitude Nightside Martian magnetic topology using electron pitch angle distributions. J. Geophys. Res.: Space Phys., 122(10), 9777–9789.

Withers, P., Fillingim, M. O., Lillis, R. J., Häusler, B., Hinson, D. P., Tyler, G. L., Pätzold, M., Peter, K., Tellmann, S., and Witasse, O. (2012). Observations of the nightside ionosphere of Mars by the Mars Express Radio Science Experiment (MaRS). J. Geophys. Res.: Space Phys., 117(A12), A12307.

Wu, X. S., Cui, J., Cao, Y. T., Liu, L. J., Zhou, Z. J., Huang, Y. Y., He, F., and Wei, Y. (2019a). On the hardness of the photoelectron energy spectrum near Mars. J. Geophys. Res.: Planets, 124(11), 2745–2753.

Wu, X. S., Cui, J., Yu, J., Liu, L. J., and Zhou, Z. J. (2019b). Photoelectron balance in the dayside Martian upper atmosphere. Earth Planet. Phys., 3(5), 373–379.

Wu, X. S., Cui, J., Xu, S. S., Lillis, R. J., Yelle, R. V., Edberg, N. J. T., Vigren, E., Rong, Z. J., Fan, K., … Mitchell, D. L. (2019c). The morphology of the topside Martian ionosphere: implications on bulk ion flow. J. Geophys. Res.: Planets, 124(3), 734–751.

Xu, S. S., Mitchell, D., Liemohn, M., Dong, C. F., Bougher, S., Fillingim, M., Lillis, R., McFadden, J., Mazelle, C., … Jakosky, B. (2016). Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere source. Geophys. Res. Lett., 43(17), 8876–8884.

Xu, S. S., Mitchell, D., Liemohn, M., Fang, X. H., Ma, Y. J., Luhmann, J., Brain, D., Steckiewicz, M., Mazelle, C., … Jakosky, B. (2017). Martian low-altitude magnetic topology deduced from MAVEN/SWEA observations. J. Geophys. Res.: Space Phys., 122(2), 1831–1852.

Xu, S. S., Mitchell, D., Luhmann, J., Ma, Y. J., Fang, X. H., Harada, Y., Hara, T., Brain, D., Weber, T., … DiBraccio, G. A. (2017). High-altitude closed magnetic loops at mars observed by MAVEN. Geophys. Res. Lett., 44(22), 11,229–11,238.

Xu, S. S., Weber, T., Mitchell, D. L., Brain, D. A., Mazelle, C., DiBraccio, G. A., and Espley, J. (2019). A technique to infer magnetic topology at mars and its application to the terminator region. J. Geophys. Res.: Space Phys., 124(3), 1823–1842.

Yang, C., Su, Z. P., Xiao, F. L., Zheng, H. N., Wang, Y. M., Wang, S., Spence, H. E., Reeves, G. D., Baker, D. N.,… Funsten, H. O. (2017). A positive correlation between energetic electron butterfly distributions and magnetosonic waves in the radiation belt slot region. Geophys. Res. Lett., 44(9), 3980–3990.

Zhang, M. H. G., Luhmann, J. G., and Kliore, A. J. (1990). An observational study of the nightside ionospheres of Mars and Venus with radio occultation methods. J. Geophys. Res.: Space Phys., 95(A10), 17,095–17,102.


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Bidirectional electron conic observations for photoelectrons in the Martian ionosphere

YuTian Cao, Jun Cui, BinBin Ni, XiaoShu Wu, Qiong Luo, ZhaoGuo He