SMuK 2021 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 2: Sun and Heliosphere II
EP 2.4: Talk
Monday, August 30, 2021, 17:30–17:45, H7
3He measurements by the Suprathermal Ion Telescope on STEREO-A during solar cycle 24 and their association with electrons observed by SEPT and STE — •Marlon Köberle1, Radoslav Bucik2, Bernd Heber1, Andreas Klassen1, and Linghua Wang3 — 1Christian-Albrechts-Universität zu Kiel, Germany — 2Southwest Research Institute, San Antonio, USA — 3Institute of Space Physics and Applied Technology, Peking University, Peking, China
3He-rich solar energetic particle (SEP) events are characterized by a peculiar elemental composition with rare species like 3He or ultra-heavy ions tremendously enhanced over the solar system abundances.
Previous studies have shown that the enormous enhancement of 3He up to a factor of 104 above coronal abundances seems to be uncorrelated with the enhancement factor of heavier ions, indicating different acceleration mechanisms.
The Suprathermal Ion Telescope (SIT) is a time-of-flight mass spectrometer designed to measure ions in the energy range of a few tens of keV up to several MeV per nucleon.
The mass resolution of SIT doesnt allow to easily distinguish between 3He and 4He especially in cases of a low 3He to 4He ratio.
Here we present our semi-automatic detection approach that allowed us to identify 112 3He rich periods between 2007 and 2020, covering the whole solar cycle 24.
A comparison between the Fe/O and 3He/4He ratios showed no correlation supporting the present picture.
Additionally an association of ≈60% of the periods could be found with in-situ electron measurements by STEREO-SEPT and STEREO-STE.