scholarly journals The effects of drift and winds on the propagation of Galactic cosmic rays

2021 ◽  
Author(s):  
A AL-Zetoun ◽  
A Achterberg
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Field Model ◽  
Galactic Cosmic Rays ◽  
Galactic Magnetic Field ◽  
Galactic Wind ◽  
Wind Speeds ◽  
Field Diffusion ◽  
The Galaxy ◽  
Magnetic Field Model

Abstract We study the effects of drift motions and the advection by a Galactic wind on the propagation of cosmic rays in the Galaxy. We employ a simplified magnetic field model, based on (and similar to) the Jansson-Farrar model for the Galactic magnetic field. Diffusion is allowed to be anisotropic. The relevant equations are solved numerically, using a set of stochastic differential equations. Inclusion of drift and a Galactic wind significantly shortens the residence time of cosmic rays, even for moderate wind speeds.

scholarly journals Progress in the Global Modeling of the Galactic Magnetic Field

2019 ◽  
Vol 210 ◽  
pp. 04005 ◽  
Author(s):  
Michael Unger ◽  
Glennys Farrar
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Synchrotron Emission ◽  
Ultrahigh Energy ◽  
Galactic Magnetic Field ◽  
Global Modeling ◽  
Emission Data ◽  
The Galaxy ◽  
Ultrahigh Energy Cosmic Rays ◽  
The Impact

We discuss the global modeling of the properties of the Galactic Magnetic Field (GMF). Several improvements and variations of the model of the GMF from Jansson & Farrar (2012) (JF12) are investigated in an analysis constrained by all-sky rotation measures of extragalactic sources and polarized and unpolarized synchrotron emission data from WMAP and Planck. We present the impact of the investigated model variations on the propagation of ultrahigh-energy cosmic rays in the Galaxy

scholarly journals Cosmic rays and stochastic magnetic reconnection in the heliotail

2012 ◽  
Vol 19 (3) ◽  
pp. 351-364 ◽  
Author(s):  
P. Desiati ◽  
A. Lazarian
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Magnetic Reconnection ◽  
Supernova Remnants ◽  
Average Energy ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Shock Acceleration ◽  
Diffusive Shock Acceleration ◽  
The Galaxy

Abstract. Galactic cosmic rays are believed to be generated by diffusive shock acceleration processes in Supernova Remnants, and the arrival direction is likely determined by the distribution of their sources throughout the Galaxy, in particular by the nearest and youngest ones. Transport to Earth through the interstellar medium is expected to affect the cosmic ray properties as well. However, the observed anisotropy of TeV cosmic rays and its energy dependence cannot be explained with diffusion models of particle propagation in the Galaxy. Within a distance of a few parsec, diffusion regime is not valid and particles with energy below about 100 TeV must be influenced by the heliosphere and its elongated tail. The observation of a highly significant localized excess region of cosmic rays from the apparent direction of the downstream interstellar flow at 1–10 TeV energies might provide the first experimental evidence that the heliotail can affect the transport of energetic particles. In particular, TeV cosmic rays propagating through the heliotail interact with the 100–300 AU wide magnetic field polarity domains generated by the 11 yr cycles. Since the strength of non-linear convective processes is expected to be larger than viscous damping, the plasma in the heliotail is turbulent. Where magnetic field domains converge on each other due to solar wind gradient, stochastic magnetic reconnection likely occurs. Such processes may be efficient enough to re-accelerate a fraction of TeV particles as long as scattering processes are not strong. Therefore, the fractional excess of TeV cosmic rays from the narrow region toward the heliotail direction traces sightlines with the lowest smearing scattering effects, that can also explain the observation of a harder than average energy spectrum.

scholarly journals F. Magnetic Fields, Pulsars, X-Ray And Gamma-Ray Emission

1985 ◽  
Vol 19 (1) ◽  
pp. 431-435
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Gamma Ray ◽  
Logarithmic Spiral ◽  
Radio Sources ◽  
Galactic Magnetic Field ◽  
Rotation Measure ◽  
The Galaxy ◽  
Magnetic Field Model ◽  
Characteristic Features

During the triennium under review many papers reported on studies of the structure of the galactic magnetic field. Andreasyan used rotation measures (RM) of large samples of extra-galactic radio sources and pulsars (29.156.001) or radio sources (32.156.002), and Inoue and Tabara (31.156.011) used in addition optical polarization of stars to investigate the direction of the large-scale regular magnetic field. Thomson and Nelson analyse the RMs of 459 extragalactic sources (32. 161.001) to determine the best fit parameters for a galactic magnetic-field model, and find agreement with their earlier work using pulsars (27.156.009). Similarly, Sofue and Fujimoto (33.155.011) show that the characteristic features of the RM distribution on the sky are well reproduced by a model in which the magnetic field is in a bisymmetric, two-armed logarithmic spiral configuration. Finally, Welter, Perry and Kronberg (37.159.096) present a statistical analysis of the (Galaxy-corrected) residual rotation measure (RRM) of 116 QSOs.

scholarly journals Solenoidal Improvements for the JF12 Galactic Magnetic Field Model

2019 ◽  
Vol 877 (2) ◽  
pp. 76 ◽  
Author(s):  
Jens Kleimann ◽  
Timo Schorlepp ◽  
Lukas Merten ◽  
Julia Becker Tjus
Keyword(s):  
Magnetic Field ◽  
Field Model ◽  
Galactic Magnetic Field ◽  
Magnetic Field Model

scholarly journals Observational Aspects of Galactic Magnetic Fields

1970 ◽  
Vol 39 ◽  
pp. 150-167 ◽  
Author(s):  
G. L. Verschuur
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Field Model ◽  
Continuum Emission ◽  
Radio Sources ◽  
Galactic Magnetic Fields ◽  
The Galaxy ◽  
Magnetic Field Model ◽  
Galactic Radio ◽  
Polarized Radiation

I will review the impressive advances in the observations of the galactic magnetic field made since the time of van de Hulst's review at the 1966 Noordwijk Symposium (van de Hulst, 1967). Most of these observations are so recent that the consequences have not yet been worked out very well and are in need of discussion. Luckily the emphasis in the present Symposium, unlike that in many others, is on discussion. For this reason I will not hesitate to include in my review provocative speculations. I will base my discussion on Mathewson's (1968) elegant magnetic field model, consisting of a local field in the form of a sheared helix, superimposed on a large scale longitudinal field. I will include the criticism of this model by Gardner et al. (1969b). Mathewson has succeeded in accounting for such data as the distribution of background polarized radiation from the Galaxy, the distribution of rotation measures of extra-galactic radio sources and even the spurs and ridges in galactic continuum emission. There are critics who inherently distrust models that account for too many things at one time, but I feel that we should try to account for as many things as possible with the least number of models. Mathewson has succeeded in uniting much data and I will only add a few pieces to his model.

scholarly journals The Galactic magnetic field and its lensing of ultrahigh energy and Galactic cosmic rays

2015 ◽  
Vol 11 (A29B) ◽  
pp. 723-726 ◽  
Author(s):  
Glennys R. Farrar
Keyword(s):  
Magnetic Field ◽  
Dark Matter ◽  
Cosmic Rays ◽  
Solar System ◽  
Magnetic Fields ◽  
Galactic Cosmic Rays ◽  
Ultrahigh Energy ◽  
Galactic Magnetic Field ◽  
Ultrahigh Energy Cosmic Rays

AbstractIt has long been recognized that magnetic fields play an important role in many astrophysical environments, yet the strength and structure of magnetic fields beyond our solar system have been at best only qualitatively constrained. The Galactic magnetic field in particular is crucial for modeling the transport of Galactic CRs, for calculating the background to dark matter and CMB-cosmology studies, and for determining the sources of UHECRs. This report gives a brief overview of recent major advances in our understanding of the Galactic magnetic field (GMF) and its lensing of Galactic and ultrahigh energy cosmic rays.

scholarly journals The Galactic Magnetic Field and Cosmic Rays

1970 ◽  
Vol 23 (5) ◽  
pp. 731 ◽  
Author(s):  
JH Piddington
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Local System ◽  
Galactic Magnetic Field ◽  
Galactic Field ◽  
General Field ◽  
The Galaxy ◽  
Coronal Field ◽  
The Magnetic Field

The structure of the magnetic field of the Galaxy and other spiral systems and the inseparable problem of the origin of cosmic rays are examined: (1) A variety of evidence is used to show that the galactic field extends far beyond the disk and connects the disk field with a general field fixed in the local system of galaxies. (2) The coronal field extends beyond 10 kpc as an oblique helix which is constantly expanding, and has partially force�free characteristics.

scholarly journals On particle acceleration and transport in plasmas in the Galaxy: theory and observations

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Elena Amato ◽  
Sabrina Casanova
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Quality Data ◽  
Current Status ◽  
The Earth ◽  
The Galaxy ◽  
Formation And Evolution ◽  
Galaxy Assembly

Accelerated particles are ubiquitous in the Cosmos and play a fundamental role in many processes governing the evolution of the Universe at all scales, from the sub-AU scale relevant for the formation and evolution of stars and planets to the Mpc scale involved in Galaxy assembly. We reveal the presence of energetic particles in many classes of astrophysical sources thanks to their production of non-thermal radiation, and we detect them directly at the Earth as cosmic rays. In the last two decades both direct and indirect observations have provided us a wealth of new, high-quality data about cosmic rays and their interactions both in sources and during propagation, in the Galaxy and in the Solar System. Some of the new data have confirmed existing theories about particle acceleration and propagation and their interplay with the environment in which they occur. Some others have brought about interesting surprises, whose interpretation is not straightforward within the standard framework and may require a change of paradigm in terms of our ideas about the origin of cosmic rays of different species or in different energy ranges. In this article, we focus on cosmic rays of galactic origin, namely with energies below a few petaelectronvolts, where a steepening is observed in the spectrum of energetic particles detected at the Earth. We review the recent observational findings and the current status of the theory about the origin and propagation of galactic cosmic rays.

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