Transport of Cosmic-Ray Electrons from 1 au to the Sun
Gamma rays are produced by cosmic-ray (CR) protons interacting with the particles at the solar photosphere and by CR electrons and positrons (CRes) via inverse Compton scattering of solar photons. The former comes from the solar disk while the latter extends beyond the disk. Evaluation of these emis...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2023-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/aca474 |
| _version_ | 1797697252181934080 |
|---|---|
| author | Vahé Petrosian Elena Orlando Andrew Strong |
| author_facet | Vahé Petrosian Elena Orlando Andrew Strong |
| author_sort | Vahé Petrosian |
| collection | DOAJ |
| description | Gamma rays are produced by cosmic-ray (CR) protons interacting with the particles at the solar photosphere and by CR electrons and positrons (CRes) via inverse Compton scattering of solar photons. The former comes from the solar disk while the latter extends beyond the disk. Evaluation of these emissions requires the flux and spectrum of CRs in the vicinity of the Sun, while most observations provide flux and spectra near the Earth, at around 1 au from the Sun. Past estimates of the quiet Sun gamma-ray emission use phenomenological modulation procedures to estimate spectra near the Sun. We show that CRe transport in the inner heliosphere requires a kinetic approach and use a novel approximation to determine the variation of CRe flux and spectrum from 1 au to the Sun including the effects of (1) the structure of the large-scale magnetic field, (2) small scale turbulence in the solar wind from several in situ measurements, in particular, those by Parker Solar Probe that extend this information to 0.1 au, and (3) most importantly, energy losses due to synchrotron and inverse Compton processes. We present results on the flux and spectrum variation of CRes from 1 au to the Sun for several transport models. In forthcoming papers we will use these results for a more accurate estimate of quiet Sun inverse Compton gamma-ray spectra, and, for the first time, the spectra of extreme ultraviolet to hard X-ray photons produced by synchrotron emission. These can be compared with the quiet Sun gamma-ray observation by the Fermi and X-ray upper limits set by RHESSI. |
| first_indexed | 2024-03-12T03:37:40Z |
| format | Article |
| id | doaj.art-53b07497a8d14937a9d5d8d57eb4c219 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:37:40Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-53b07497a8d14937a9d5d8d57eb4c2192023-09-03T13:07:56ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194312110.3847/1538-4357/aca474Transport of Cosmic-Ray Electrons from 1 au to the SunVahé Petrosian0https://orcid.org/0000-0002-2670-8942Elena Orlando1Andrew Strong2https://orcid.org/0000-0003-3799-5489Department of Physics, Stanford University , 382 Via Pueblo Mall, Stanford, CA 94305-4060, USA ; vahep@stanford.edu; Kavli Institute for Particle Astrophysics and Cosmology, Stanford University , Stanford, CA, USA; Department of Applied Physics, Stanford University , Stanford, CA, USAKavli Institute for Particle Astrophysics and Cosmology, Stanford University , Stanford, CA, USA; Department of Physics, University of Trieste , Trieste, Italy; National Institute for Nuclear Physics (INFN) , Trieste, ItalyMax-Planck-Institut für extraterrestrische Physik , Garching, GermanyGamma rays are produced by cosmic-ray (CR) protons interacting with the particles at the solar photosphere and by CR electrons and positrons (CRes) via inverse Compton scattering of solar photons. The former comes from the solar disk while the latter extends beyond the disk. Evaluation of these emissions requires the flux and spectrum of CRs in the vicinity of the Sun, while most observations provide flux and spectra near the Earth, at around 1 au from the Sun. Past estimates of the quiet Sun gamma-ray emission use phenomenological modulation procedures to estimate spectra near the Sun. We show that CRe transport in the inner heliosphere requires a kinetic approach and use a novel approximation to determine the variation of CRe flux and spectrum from 1 au to the Sun including the effects of (1) the structure of the large-scale magnetic field, (2) small scale turbulence in the solar wind from several in situ measurements, in particular, those by Parker Solar Probe that extend this information to 0.1 au, and (3) most importantly, energy losses due to synchrotron and inverse Compton processes. We present results on the flux and spectrum variation of CRes from 1 au to the Sun for several transport models. In forthcoming papers we will use these results for a more accurate estimate of quiet Sun inverse Compton gamma-ray spectra, and, for the first time, the spectra of extreme ultraviolet to hard X-ray photons produced by synchrotron emission. These can be compared with the quiet Sun gamma-ray observation by the Fermi and X-ray upper limits set by RHESSI.https://doi.org/10.3847/1538-4357/aca474Cosmic raysSolar windInterplanetary turbulence |
| spellingShingle | Vahé Petrosian Elena Orlando Andrew Strong Transport of Cosmic-Ray Electrons from 1 au to the Sun The Astrophysical Journal Cosmic rays Solar wind Interplanetary turbulence |
| title | Transport of Cosmic-Ray Electrons from 1 au to the Sun |
| title_full | Transport of Cosmic-Ray Electrons from 1 au to the Sun |
| title_fullStr | Transport of Cosmic-Ray Electrons from 1 au to the Sun |
| title_full_unstemmed | Transport of Cosmic-Ray Electrons from 1 au to the Sun |
| title_short | Transport of Cosmic-Ray Electrons from 1 au to the Sun |
| title_sort | transport of cosmic ray electrons from 1 au to the sun |
| topic | Cosmic rays Solar wind Interplanetary turbulence |
| url | https://doi.org/10.3847/1538-4357/aca474 |
| work_keys_str_mv | AT vahepetrosian transportofcosmicrayelectronsfrom1autothesun AT elenaorlando transportofcosmicrayelectronsfrom1autothesun AT andrewstrong transportofcosmicrayelectronsfrom1autothesun |