Erlangen 2026 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 9: Sun and Heliosphere III
EP 9.3: Vortrag
Donnerstag, 19. März 2026, 14:15–14:30, KH 01.019
Unusual Sun-Earth magnetic connections during relativistic solar particle events — K.-L. Klein2, •B. Heber1, M. Hörlöck1, S. Jensen1, P. Kühl1, and H. Sierks3 — 1Christian-Albrechts-Universität zu Kiel (CAU), Kiel, Germany — 2LIRA, Observatoire de Paris, France — 3MPI für Sonnensystemforschung, Göttingen, Germany
The Sun accelerates charged particles sometimes to relativistic energies during eruptive events. leading to so called ’Ground-Level Enhancement’ (GLE). Observations of the solar atmosphere at EUV, X-ray, and radio wavelengths provide insight into the dynamics of the coronal magnetic structures during eruptive flares. The timing of the onset of a GLE with respect to the solar eruption is therefore a primary diagnostic tool for identifying the time and place where the relativistic protons are released. Recent numerical simulations suggest that gradient and curvature drifts near and in the heliospheric current sheet may be essential for relativistic protons to reach the Earth when the eruption occurs far from the footpoint of the magnetic field line connecting the Earth with the Sun. If drifts favor protons at Earth, they should hinder electrons. In contrast to this prediction, relativistic electron observations during GLEs between 1991 and 2025 show that the first electrons arrive at Earth within a few minutes of the GLE onset. We present an alternative scenario where radio observations suggest a transient magnetic connection established between the Earth and an eruptive region behind the solar limb.
Keywords: Galactic cosmic rays; Modulation; Measurements