Relativistic Proton Levels from Region AR 12673 (GLE #72) and the Heliospheric Current Sheet as a Sun-Earth Magnetic Connection

Autor(es)

Augusto, C. R. A. ^[1] ; Navia, C. E. ^[1] ; de Oliveira, M. N. ^[1] ; Nepomuceno, A. A. ^[2] ; Fauth, A. C. ^[3] ; Kopenkin, V. ^[4] ; Sinzi, T. ^[5]

Afiliação do(s) autor(es)

^[1] Univ Fed Fluminense, Inst Fis, BR-24210346 Rio De Janeiro - Brazil

^[2] Univ Fed Fluminense, Dept Ciencias Nat, BR-28895532 Rio Das Ostras, RJ - Brazil

^[3] Univ Estadual Campinas, Inst Fis Gleb Wathagin, BR-13083859 Campinas, SP - Brazil

^[4] Waseda Univ, Res Inst Sci & Engn, Shinjuku Ku, Tokyo 169 - Japan

^[5] Rikkyo Univ, Toshima Ku, Tokyo 171 - Japan

• Tipo de documento: Artigo Científico
• Fonte: Publications of the Astronomical Society of the Pacific; v. 131, n. 996 FEB 2019.
• Citações Web of Science: 2

Resumo

On 2017 September 10 Neutron Monitors (NMs) apparatus located at ground level and high latitudes detected an increase in the counting rate associated to solar energetic particles (SEPs) emission from X8.2-class solar flare and its associated CME. This was the second-highest flare of the current solar cycle. The origin was the active region AR 12673 when it was located at the edge of the west solar disk, magnetically poorly connected with Earth. However, there was a peculiar condition: the solar protons accelerated by the CME shocks were injected within a heliospheric current sheet (HCS) region when Earth was crossing this region. We show that often HCS and SEPs propagation are closely related. If the source locations of SEPs are within or close to HCS, the HCS play the role of a Sun-Earth magnetic connection. SEPs drift around HCS paths, and SEPs are also drift in a wide range of longitudes by the HCSs. In some cases, and especially when Earth crosses the HCS sector, a fraction of these particles can reach Earth with a harder energetic particle flux, triggering a ground-level enhancement (GLE). The blast on 2017 September 10, which triggered the GLE \#72, was the second in the current solar cycle. We show that the two GLEs, including all sub-GLEs observed in the current solar cycle, comes from solar explosions that happened within an HCS structure; this behavior is also observed in the GLEs of the previous solar cycle. In general, solar explosions from active regions poorly connected with Earth can trigger GLEs, through the mechanism described above. In all cases, the SEPs drift processes by HCS structures provides an efficient particle transport, allowing the observation of these solar transient events. (AU)

• Processo FAPESP: 11/50193-4 - Detecção e estudo de eventos solares transientes e variação climática
• Beneficiário: Anderson Campos Fauth
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular