Comparative Analysis of Ion and Electron Contributions to Ionospheric Ionization at Auroral and Subauroral Latitudes
Abstract Electron and proton precipitation into the nightside ionosphere is a key process in magnetosphere–ionosphere coupling. Although auroral electron precipitation at –10 keV is traditionally considered the main driver of auroral emissions, recent studies show that keV electrons and protons can significantly contribute to ionospheric energy deposition, especially during storms. While energetic electron precipitation has been studied extensively, the role of energetic proton precipitation remains poorly quantified. Here, we use coordinated ELFIN and DMSP nightside observations during two substorm events, resolving electron and proton precipitation spectra from eV to ∼MeV. We show that keV proton precipitation, consistent with curvature scattering, can have an impact on E‐region ionization comparable to that of energetic electrons. These analyses are further supported by magnetospheric observations from the Arase and THEMIS spacecraft and ground‐based incoherent scatter radar measurements from PFISR.
Authors
- Yoshiya Kasahara (ORCID: https://orcid.org/0000-0002-9304-8235)
- Shoya Matsuda (ORCID: https://orcid.org/0000-0003-4778-8897)
- Iku Shinohara (ORCID: https://orcid.org/0000-0003-2700-0353)
- Kazuhiro Yamamoto (ORCID: https://orcid.org/0000-0002-2515-8643)
- Jun Liang (ORCID: https://orcid.org/0000-0002-4590-2978)
- S. R. Kamaletdinov (ORCID: https://orcid.org/0000-0002-2261-0331)
- Xiao‐Jia Zhang (ORCID: https://orcid.org/0000-0002-4185-5465)
- Y. Nishimura (ORCID: https://orcid.org/0000-0003-3126-4394)
- Shoichiro Yokota (ORCID: https://orcid.org/0000-0001-8851-9146)
- Yangyang Shen (ORCID: https://orcid.org/0000-0003-1969-5597)
- M. Teramoto (ORCID: https://orcid.org/0000-0001-5983-1149)
- Anton Artemyev (ORCID: https://orcid.org/0000-0001-8823-4474)
- Kazushi Asamura (ORCID: https://orcid.org/0000-0002-6076-3814)
- K. Keika (ORCID: https://orcid.org/0000-0003-0265-4318)
- Atsushi Kumamoto (ORCID: https://orcid.org/0000-0002-3988-1488)
- Tomoaki Hori (ORCID: https://orcid.org/0000-0001-8451-6941)
- Ayako Matsuoka (ORCID: https://orcid.org/0000-0001-5777-9711)
- V. Angelopoulos (ORCID: https://orcid.org/0000-0001-7024-1561)
- Asti Bhatt (ORCID: https://orcid.org/0000-0002-8881-5348)
- Satoshi Kasahara (ORCID: https://orcid.org/0000-0002-3479-772X)
- Yoshizumi Miyoshi (ORCID: https://orcid.org/0000-0001-7998-1240)
- Atsuki Shinbori (ORCID: https://orcid.org/0000-0003-4519-4526)
- F. Tsuchiya
Institutions
- Kanazawa University (JP)
- SRI International (US)
- Planetary Science Institute (US)
- Osaka University of Economics (JP)
- University of Alberta (CA)
- University of California, Los Angeles (US)
- The University of Texas at Dallas (US)
- University of Calgary (CA)
- The University of Texas at Arlington (US)
- Tohoku University (JP)
- Kyushu Institute of Technology (JP)
- Kyoto University (JP)
- Japan Aerospace Exploration Agency (JP)
- Osaka City University (JP)
- Institute of Space and Astronautical Science (JP)
- Astronomy and Space (AU)
- Nagoya University (JP)
- The University of Tokyo (JP)
- The University of Osaka (JP)
Publication Details
- Journal
- Geophysical Research Letters
- Published
- 2026-08-18
- DOI
- https://doi.org/10.1029/2026gl123777
- Primary Topic
- Ionosphere and magnetosphere dynamics
- Type
- article
- Field-Weighted Citation Impact
- 0.00