Heidelberg 2022 – scientific programme

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PV: Plenarvorträge

PV VIII

PV VIII: Plenary Talk

Thursday, March 24, 2022, 09:45–10:30, Audimax

The Sun as a source of high-energy particles — •Rami Vainio — Department of Physics and Astronomy, University of Turku, Turku, Finland

Particle acceleration at the Sun occurs in Solar Energetic Particle (SEP) events related to solar eruptions: solar flares and coronal mass ejections. Composition, timing and duration as well as other observational properties of SEP events can be used to assess the mechanisms of particle acceleration at play in these events. However, one particular complication in these analyses has been the relatively large distance of our observers to the source, both in radial and angular distance from the core of the solar eruption. Transport effects can distort the observed particle event substantially and signatures of the acceleration process may be washed out. In the last years, however, the heliospheric research community has obtained new tools to assess a large number of problems with the launch of three new space missions to the inner heliosphere in orbits around the Sun: NASA's Parker Solar Probe and ESA's Solar Orbiter and BepiColombo. In combination with older probes at Earth's distance from the Sun, they offer an unprecedented possibility to disentangle transport effects from the imprints of particle acceleration in the data.

I will provide an overview of observations and models of SEP events and discuss what has been learnt of particle acceleration at the Sun based on the comparison of models and observations. I will conclude with some of the open questions that we expect to solve over the next solar maximum with the new heliospheric fleet.