A New Monitor for Cosmic Rays in the Solar System: Inverse-Compton Emission from Cosmic-Ray Electrons Scattering with Sunlight

Project Information

SolarIC

Grant agreement ID: 844664

DOI

10.3030/844664

Project terminated on 2 August 2020

EC signature date 10 April 2019

Start date 1 September 2019

End date 31 August 2021

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 175 572,48

EU contribution

€ 175 572,48

Coordinated by

UNIVERSITEIT VAN AMSTERDAM
Netherlands

Periodic Reporting for period 1 - SolarIC (A New Monitor for Cosmic Rays in the Solar System: Inverse-Compton Emission from Cosmic-Ray Electrons Scattering with Sunlight)

Reporting period: 2019-09-01 to 2021-08-31

Summary of the context and overall objectives of the project

The project (named SolarIC) aims to study the problem of how cosmic rays interact with the Sun. Gamma rays from the Sun has recently been detected, and has many interesting properties. However, detailed theoretical understanding is lacking, which limits the potential of using these gamma rays as a probe of cosmic rays physics in the solar system as well as physics of the Sun. The overall goal of SolarIC is, through both observational and theoretical studies, to realize gamma-ray observation as a novel probe of the Sun as well as cosmic-ray propagation in the solar system.

There are two main problems that this project could address. 1) Current gamma-ray observations of the Sun lacks theoretical understanding, and lacks detailed observational exploration. In particular, many of the gamma-ray observations from the solar atmosphere itself is unexplained. 2) These gamma ray production depends on cosmic-ray propagation in the solar system, in particular in the volume between the Earth and the Sun. The properties of the cosmic rays propagation in this volume is poorly understood, and difficult send detector to directly study. Gamma rays could therefore provide an indirect mean to study this.

Understanding this problem is important, as the activities in the solar atmosphere and the how charged particles propagate in the solar system are important components of space weather, which significantly affects satellite operation, astronaut safety, and terrestrial electrical infrastructures. Gamma rays could be a new tool to study this problem, which may offer new insights for better and more accurate space weather modeling.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the project period, I have successfully implemented a simulation of cosmic-ray propagation near the solar atmosphere with the presence of magnetic fields. This is one of the first studies that was able to do that. In particular, we considered the magnetic fields above the surface of the Sun, and showed that these magnetic fields alone can significantly affect the gamma-ray production, but not enough to explain high-energy gamma rays observed during solar minimum. This work paves the way for further improvement of the simulation and studies of cosmic rays near the Sun with magnetic fields.

In addition, I have successful hosted two workshops, one for bachelor students and one for master students. During the workshop, we designed research projects with sub-tasks that these students can take on under our guidance. Both workshops are successful, and results are in preparation for publication. These workshops constitutes important learning experience for the students.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

We have shown that magnetic fields above the Sun could significantly enhance the gamma-ray production caused by cosmic rays, but it is not enough to explain the high-energy observation during the solar minimum. While this works demystified a lot of physics behind how solar gamma-ray production are enhanced by magnetic fields, it also shows new ideas are needed to explain the solar minimum observation, and more detailed study is needed for quantitative study. This highlights the importance and usefulness of gamma rays as a probe for conditions of the Sun in the future.

For the student projects, we showed that KM3NeT, the flagship European neutrino telescope can be one of the world's most sensitive dark matter detector, after considering its unique capabilities. Thus, in the future KM3NeT should shed light on the problem of dark matter, one of the most important problem in modern physics.

The main results from arxiv:2009.03888