Tesema, F., Partamies, N., Nesse Tyssøy, H., Kero, A., & Smith‐Johnsen, C. (2020). Observations of electron precipitation during pulsating aurora and its chemical impact. Journal of Geophysical Research: Space Physics, 125, e2019JA027713. https://doi.org/10.1029/2019JA027713
Observations of electron precipitation during pulsating aurora and its chemical impact
|Author:||Tesema, Fasil1,2; Partamies, Noora3,2; Tyssøy, H. Nesse2;|
1Department of Arctic Geophysics, The University Centre in Svalbard, Longyearbyen, Norway
2Birkeland Centre for Space Science, University of Bergen, Bergen, Norway
31Department of Arctic Geophysics, The University Centre in Svalbard, Longyearbyen, Norway
4Sodankylä Geophysical Observatory, University of Oulu, Oulu, Finland
|Online Access:||PDF Full Text (PDF, 4.1 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2020092475686
American Geophysical Union,
|Publish Date:|| 2020-09-24
Pulsating auroras (PsAs) are low‐intensity diffuse aurora, which switch on and off with a quasiperiodic oscillation period from a few seconds to ∼10 s. They are predominantly observed after magnetic midnight, during the recovery phase of substorms and at the equatorward boundary of the auroral oval. PsAs are caused by precipitating energetic electrons, which span a wide range of energies between tens and hundreds of keV. Such energetic PsA electrons will deposit their energy at mesospheric altitudes and induce atmospheric chemical changes. To examine the effects of energetic PsA electrons on the atmosphere, we first collect electron flux and energy measurements from low‐latitude spacecraft to construct a typical energy spectrum of precipitating electrons during PsA. Among the 840 PsA events identified using ground‐based auroral all‐sky camera (ASC) network over the Fennoscandian region, 253 events were observed by DMSP, POES, and FAST spacecraft over the common field of view of five ASCs. The combined measurements from these spacecraft enable us to obtain an energy spectrum consisting of nonrelativistic and relativistic (30 eV to 1,000 keV) electrons during PsA. The median spectrum was found to be in good agreement with earlier estimates of the PsA spectra. We then use the Sodankylä Ion‐neutral Chemistry (SIC) model to assess the chemical effect of PsA electrons. The observed extreme and median spectra of PsA produce a significant depletion in the mesospheric odd oxygen concentration up to 78%.
Journal of geophysical research. Space physics
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
115 Astronomy and space science
The funding support for F. Tesema and H. Nesse Tyssøy work is provided by the Norwegain Research Council (NRC) under CoE Contract 223252. In addition, the work of N. Partamies is supported by NRC project 287427. The work of C. Smith‐Johnsen is supported by the NRC project 263008. The work of Antti Kero is funded by the Tenure Track Project in Radio Science at Sodankylä Geophysical Observatory/University of Oulu.
MIRACLE ASC quicklook data are available at the website (https://space.fmi.fi/MIRACLE/ASC/?page=keograms), and full‐resolution image data can be requested from FMI (email@example.com). The entire FAST mission data can be found online (http://sprg.ssl.berkeley.edu/fast/). DMSP particle data are available at CEDAR madrigal database (http://cedar.openmadrigal.org). Event lists, precipitating electrons energy from DMSP, POES, and FAST spacecraft, and SIC model outputs used in this study are available in Tesema et al. (2019).
© 2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.