scholarly journals The cosmic ray anisotropy below 10<sup>15</sup> eV

2015 ◽  
Vol 2 ◽  
pp. 27-33 ◽  
Author(s):  
G. Di Sciascio
Keyword(s):  
Magnetic Field ◽  
Standard Model ◽  
Northern Hemisphere ◽  
Scientific Community ◽  
Cosmic Ray ◽  
Local Magnetic Field ◽  
Two Dimensional ◽  
Arrival Direction ◽  
The Standard Model ◽  
The Galaxy

Abstract. The measurement of the anisotropy in the cosmic ray (CR) arrival direction distribution provides important informations on the propagation mechanisms and on the identification of their sources. In the last decade the anisotropy came back to the attention of the scientific community, thanks to several new two-dimensional representations of the CR arrival direction distribution which clearly showed the existence of anisotropies at different angular scales in both hemispheres. The origin of the observed anisotropies is still unknown. So far, no theory of CRs in the Galaxy exists yet to explain the observations leaving the standard model of CRs and that of the local magnetic field unchanged at the same time. In this paper the observations of Galactic CR anisotropy will be briefly summarized, with particular attention to the results obtained by the ARGO-YBJ experiment in the Northern Hemisphere.

scholarly journals TeV Cosmic Ray Anisotropy and the Heliospheric Magnetic Field

2014 ◽  
Vol 1 ◽  
pp. 65-71 ◽  
Author(s):  
P. Desiati ◽  
A. Lazarian
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Particle Distribution ◽  
Sudden Change ◽  
Cosmic Ray ◽  
Arrival Direction ◽  
Energy Dependency ◽  
The Galaxy ◽  
Different Characteristics ◽  
Cosmic Ray Flux

Abstract. Cosmic rays are observed to possess a small non uniform distribution in arrival direction. Such anisotropy appears to have a roughly consistent topology between tens of GeV and hundreds of TeV, with a smooth energy dependency on phase and amplitude. Above a few hundreds of TeV a sudden change in the topology of the anisotropy is observed. The distribution of cosmic ray sources in the Milky Way is expected to inject anisotropy on the cosmic ray flux. The nearest and most recent sources, in particular, are expected to contribute more significantly than others. Moreover the interstellar medium is expected to have different characteristics throughout the Galaxy, with different turbulent properties and injection scales. Propagation effects in the interstellar magnetic field can shape the cosmic ray particle distribution as well. In particular, in the 1–10 TeV energy range, they have a gyroradius comparable to the size of the Heliosphere, assuming a typical interstellar magnetic field strength of 3 μG. Therefore they are expected to be strongly affected by the Heliosphere in a manner ordered by the direction of the local interstellar magnetic field and of the heliotail. In this paper we discuss on the possibility that TeV cosmic rays arrival distribution might be significantly redistributed as they propagate through the Heliosphere.

scholarly journals The Origin and Dynamical Effects of the Magnetic Fields and Cosmic Rays in the Disk of the Galaxy

1970 ◽  
Vol 39 ◽  
pp. 168-183
Author(s):  
E. N. Parker
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Dynamical Behavior ◽  
Cosmic Ray ◽  
Interested Reader ◽  
Written Text ◽  
The Galaxy ◽  
Basic Ideas ◽  
The Magnetic Field

The topic of this presentation is the origin and dynamical behavior of the magnetic field and cosmic-ray gas in the disk of the Galaxy. In the space available I can do no more than mention the ideas that have been developed, with but little explanation and discussion. To make up for this inadequacy I have tried to give a complete list of references in the written text, so that the interested reader can pursue the points in depth (in particular see the review articles Parker, 1968a, 1969a, 1970). My purpose here is twofold, to outline for you the calculations and ideas that have developed thus far, and to indicate the uncertainties that remain. The basic ideas are sound, I think, but, when we come to the details, there are so many theoretical alternatives that need yet to be explored and so much that is not yet made clear by observations.

scholarly journals The relative orientation between the magnetic field and gas density structures in non-gravitating turbulent media

2020 ◽  
Vol 499 (4) ◽  
pp. 4785-4792
Author(s):  
Bastian Körtgen ◽  
Juan D Soler
Keyword(s):  
Magnetic Field ◽  
Molecular Clouds ◽  
Relative Orientation ◽  
Local Magnetic Field ◽  
Gas Formation ◽  
Initial Magnetization ◽  
The Galaxy ◽  
Dynamical Time ◽  
Isothermal Gas ◽  
The Magnetic Field

ABSTRACT Magnetic fields are a dynamically important agent for regulating structure formation in the interstellar medium. The study of the relative orientation between the local magnetic field and gas (column-) density gradient has become a powerful tool to analyse the magnetic field’s impact on the dense gas formation in the Galaxy. In this study, we perform numerical simulations of a non-gravitating, isothermal gas, where the turbulence is driven either solenoidally or compressively. We find that only simulations with an initially strong magnetic field (plasma-β &lt; 1) show a change in the preferential orientation between the magnetic field and isodensity contours, from mostly parallel at low densities to mostly perpendicular at higher densities. Hence, compressive turbulence alone is not capable of inducing the transition observed towards nearby molecular clouds. At the same high initial magnetization, we find that solenoidal modes produce a sharper transition in the relative orientation with increasing density than compressive modes. We further study the time evolution of the relative orientation and find that it remains unchanged by the turbulent forcing after one dynamical time-scale.

Cosmic-ray induced vacuum decay in the standard model

1988 ◽  
Vol 206 (3) ◽  
pp. 527-532 ◽  
Author(s):  
Marc Sher ◽  
Helmut W. Zaglauer
Keyword(s):  
Standard Model ◽  
Cosmic Ray ◽  
Vacuum Decay ◽  
The Standard Model

scholarly journals MHD Models of Galactic Center Lobes, Shells, and Filaments

1990 ◽  
Vol 140 ◽  
pp. 379-380
Author(s):  
Kazunari Shibata ◽  
Ryoji Matsumoto
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Galactic Center ◽  
Transient State ◽  
Rotating Disk ◽  
Quasi Equilibrium ◽  
Two Dimensional ◽  
The Galaxy ◽  
Field Lines

Magnetohydrodynamic (MHD) mechanisms producing radio lobes, shells, and filaments in the Galactic center as well as in the gas disk of the Galaxy are studied by using two-dimensional MHD code: (a) the explosion in a magnetized disk, (b) the interaction of a rotating disk with vertical fields, and (c) the nonlinear Parker instability in toroidal magnetic fields in a disk. In all cases, dense shells or filaments are created along magnetic field lines in a transient state, in contrast to the quasi-equilibrium filaments perpendicular to magnetic fields.

scholarly journals Deep Multi-Colour Starcounts

1994 ◽  
Vol 161 ◽  
pp. 423-424
Author(s):  
I.N. Reid ◽  
S.R. Majewski
Keyword(s):  
Standard Model ◽  
Stellar Population ◽  
Stellar Populations ◽  
The North ◽  
Halo Stars ◽  
The Standard Model ◽  
The Galaxy ◽  
Best Fitting ◽  
Galactic Stellar Populations ◽  
North Galactic

Starcounts remain one of the most effective methods of probing the structure of the Galactic stellar populations. However, studies of the distribution at large distances above the Plane demand accurate photometry extending to faint magnitudes (V &gt; 20), and such datasets are still rare. We (Reid &amp; Majewski 1993) have analyzed data from one field — Majewski's (1992) UJF observations of SA57, the North Galactic Pole field. Our results revealed significant discrepancies with the standard model of the Galaxy (see refs. in Reid &amp; Majewski), notably a paucity in the number of halo stars by a factor of two and the presence of a factor of two more disk stars than predicted — sufficient stars that the disk is the majority stellar population, outnumbering halo stars 2:1 even at V = 21. Majewski et al. (1993) has obtained UJFN photographic data for several other fields, and Fig. 1 shows a preliminary comparison of these observations with the predictions of the best-fitting SA57 model. Given that none of the parameters have been modified, the agreement is surprisingly good.

Local magnetic field distributions: Two-dimensional Ising models

1984 ◽  
Vol 30 (1) ◽  
pp. 250-258 ◽  
Author(s):  
M. Thomsen ◽  
M. F. Thorpe ◽  
T. C. Choy ◽  
D. Sherrington
Keyword(s):  
Magnetic Field ◽  
Ising Models ◽  
Local Magnetic Field ◽  
Two Dimensional ◽  
Field Distributions

scholarly journals Renormalizable Gravitational Action That Reduces to General Relativity on the Mass-Shell

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 81
Author(s):  
Peter Morley
Keyword(s):  
General Relativity ◽  
Quantum Mechanics ◽  
Standard Model ◽  
Scalar Curvature ◽  
Gravitational Constant ◽  
Mass Shell ◽  
Two Dimensional ◽  
Speed Of Light ◽  
Gravitational Action ◽  
The Standard Model

We derive the equation that relates gravity to quantum mechanics: R|mass-shell=8πGc4LSM, where R is the scalar curvature, G is the gravitational constant, c is the speed of light and LSM is the Standard Model Lagrangian, or its future replacement. Implications of this equation are discussed in the paper. In particular, we show (in the last section) that this equation is the transformation that relates four-dimensional physics to two-dimensional physics.

scholarly journals Comments on magnetic black holes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Juan Maldacena
Keyword(s):  
Magnetic Field ◽  
Black Holes ◽  
Radiation Effects ◽  
Magnetic Charge ◽  
Two Dimensional ◽  
Electroweak Symmetry ◽  
Charged Black Holes ◽  
The Standard Model ◽  
Field Lines ◽  
The Magnetic Field

Abstract We discuss aspects of magnetically charged black holes in the Standard Model. For a range of charges, we argue that the electroweak symmetry is restored in the near horizon region. The extent of this phase can be macroscopic. If Q is the integer magnetic charge, the fermions lead to order Q massless two dimensional fermions moving along the magnetic field lines. These greatly enhance Hawking radiation effects.

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