Transport of Cosmic ray electrons from 1 AU to the Sun
arXiv:2212.00929 · doi:10.3847/1538-4357/aca474
Abstract
Gamma rays are produced by cosmic ray (CR) protons interacting with the particles at solar photosphere and by cosmic ray electrons and positrons (CRes) via inverse Compton scattering of solar photons. The former come from the solar disk while the latter extend 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 (see review by Orlando and Strong 2021 and references therein). 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 effects of (1) the structure of 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 spectrum of extreme ultraviolet to hard X-ray photons produced by synchrotron emission. These can be compared with the quiet Sun gamma-ray observation by Fermi (see, e.g.~Fermi-LAT Collaboration, 2011) and X-ray upper limits set by RHESSI (Hannah et al., 2010).
arXiv comment25 pages, 11 figures, in press Astrophysical Journal
References in corpus (17)
- The Evolution and Role of Solar Wind Turbulence in the Inner Heliosphere
- Klein-Nishina Effects in the Spectra of Non-Thermal Sources Immersed in External Radiation Fields
- Stochastic Acceleration of Electrons and Protons. I. Acceleration by Parallel Propagating Waves
- Stochastic Acceleration by Turbulence
- HAWC Observations Strongly Favor Pulsar Interpretations of the Cosmic-Ray Positron Excess
- Fermi-LAT Observations of Two Gamma-Ray Emission Components from the Quiescent Sun
- The Strength and Radial Profile of Coronal Magnetic Field from the Standoff Distance of a CME-driven Shock
- Gamma-ray emission from the solar halo and disk: a study with EGRET data
- Gamma-rays from halos around stars and the Sun
- Transport phenomena in stochastic magnetic mirrors
- Stochastic Acceleration of Low Energy Electrons in Cold Plasmas
- Cosmic Ray Diffusion Coefficients Throughout The Inner Heliosphere From Global Solar Wind Simulation
- Constraining the hard X-ray properties of the quiet Sun with new RHESSI observations
- Measurement of the Open Magnetic Flux in the Inner Heliosphere down to 0.13AU
- Cascade and Damping of Alfvén-Cyclotron Fluctuations: Application to Solar Wind Turbulence Spectrum
- The Relation Between Escape and Scattering Times of Energetic Particles in a Turbulent Magnetized Plasma: Application to Solar Flares
- StellarICS: Inverse Compton Emission from the Quiet Sun and Stars from keV to TeV