scholarly journals Global simulations of a galactic dynamo driven by cosmic-rays and exploding magnetized stars

2008 ◽  
Vol 4 (S259) ◽  
pp. 549-550 ◽  
Author(s):  
Michał Hanasz ◽  
Dominik Wóltański ◽  
Kacper Kowalik ◽  
Rafał Pawłaszek
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Cosmic Ray ◽  
Small Scale ◽  
Inverse Cascade ◽  
Mhd Simulations ◽  
Magnetized Stars

AbstractWe conduct global galactic–scale magnetohydrodynamical (MHD) simulations of the cosmic–ray driven dynamo. We assume that exploding stars deposit small–scale, randomly oriented, dipolar magnetic fields into the differentially rotating ISM, together with a portion of cosmic rays, accelerated in supernova shocks. Our simulations are performed with the aid of a new parallel MHD code PIERNIK. We demonstrate that dipolar magnetic fields supplied on small SN–remnant scales, can be amplified exponentially by the CR–driven dynamo to the present equipartition values, and transformed simultaneously to large galactic–scales by an inverse cascade promoted by resistive processes.

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 On the correlation of the highest energy cosmic rays with AGNs

2009 ◽  
Vol 5 (H15) ◽  
pp. 251-253
Author(s):  
Vitor de Souza ◽  
Peter L. s Biermman
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Present Status ◽  
Cosmic Ray ◽  
Radio Galaxies ◽  
Pierre Auger Observatory ◽  
Heavy Nuclei ◽  
Measured Energy

AbstractIn this paper we briefly discuss the present status of the cosmic ray astrophysics under the light of the new data from the Pierre Auger Observatory. The measured energy spectrum is used to test the scenario of production in nearby radio galaxies. Within this framework the AGN correlation would require that most of the cosmic rays are heavy nuclei and are widely scattered by intergalactic magnetic fields.

scholarly journals Search for the astrophysical sources of the Fly's Eye event with the highest to date cosmic ray energy E=3.2·1020 eV

2016 ◽  
Vol 6 (1) ◽  
pp. 41-44 ◽  
Author(s):  
R. Gnatyk ◽  
Yu. Kudrya ◽  
V. Zhdanov
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Cosmic Ray ◽  
High Energy ◽  
Tidal Disruption ◽  
Millisecond Pulsars ◽  
Tracking Method ◽  
Primary Nucleus ◽  
High Energy Cosmic Rays

Among the registered extremely high energy cosmic rays (EHECR, E=3.2·1020 eV) an event with the highest to date energy of E=3.2·1020 eV was detected by the Fly's Eye experiment (FE event) in 1991. With the use of the back-tracking method for the calculation of the EHECR trajectories in Galactic and extragalactic magnetic fields, we show that the galaxies UGC 03574 and UGC 03394 are the most promising candidates among the nearby extragalactic sources for the cases of iron and C-N-O group primary nucleus respectively. The most likely accelerating mechanisms are the newly-born millisecond pulsars, magnetar flares and tidal disruption events in these galaxies.

scholarly journals Interstellar and intergalactic dynamos

2012 ◽  
Vol 8 (S294) ◽  
pp. 225-236
Author(s):  
M. Hanasz ◽  
D. Woltanski ◽  
K. Kowalik
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Numerical Models ◽  
Rotation Period ◽  
Cosmic Ray ◽  
Small Scale ◽  
Galactic Rotation ◽  
Galaxy Mergers ◽  
Wide Range

AbstractWe review recent developments of amplification models of galactic and intergalactic magnetic field. The most popular scenarios involve variety of physical mechanisms, including turbulence generation on a wide range of physical scales, effects of supernovae, buoyancy as well as the magnetorotational instability. Other models rely on galaxy interaction, which generate galactic and intergalactic magnetic fields during galaxy mergers. We present also global galactic-scale numerical models of the Cosmic Ray (CR) driven dynamo, which was originally proposed by Parker (1992). We conduct a series of direct CR+MHD numerical simulations of the dynamics of the interstellar medium (ISM), composed of gas, magnetic fields and CR components. We take into account CRs accelerated in randomly distributed supernova (SN) remnants, and assume that SNe deposit small-scale, randomly oriented, dipolar magnetic fields into the ISM. The amplification timescale of the large-scale magnetic field resulting from the CR-driven dynamo is comparable to the galactic rotation period. The process efficiently converts small-scale magnetic fields of SN-remnants into galactic-scale magnetic fields. The resulting magnetic field structure resembles the X-shaped magnetic fields observed in edge-on galaxies.

scholarly journals Cosmic-ray driven dynamo in galactic disks

2008 ◽  
Vol 4 (S259) ◽  
pp. 479-484 ◽  
Author(s):  
Michał Hanasz ◽  
K. Otmianowska-Mazur ◽  
H. Lesch ◽  
G. Kowal ◽  
M. Soida ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Supernova Remnants ◽  
Large Scale ◽  
Cosmic Ray ◽  
Turbulent Energy ◽  
Field Energy ◽  
Small Scale ◽  
Galactic Rotation ◽  
Dynamo Action ◽  
Magnetic Field Energy

AbstractWe present new developments on the Cosmic–Ray driven, galactic dynamo, modeled by means of direct, resistive CR–MHD simulations, performed with ZEUS and PIERNIK codes. The dynamo action, leading to the amplification of large–scale galactic magnetic fields on galactic rotation timescales, appears as a result of galactic differential rotation, buoyancy of the cosmic ray component and resistive dissipation of small–scale turbulent magnetic fields. Our new results include demonstration of the global–galactic dynamo action driven by Cosmic Rays supplied in supernova remnants. An essential outcome of the new series of global galactic dynamo models is the equipartition of the gas turbulent energy with magnetic field energy and cosmic ray energy, in saturated states of the dynamo on large galactic scales.

scholarly journals Supernova remnants and the origin of cosmic rays

2013 ◽  
Vol 9 (S296) ◽  
pp. 305-314
Author(s):  
Jacco Vink
Keyword(s):  
Synchrotron Radiation ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Long Time ◽  
Gamma Ray Emission

AbstractSupernova remnants have long been considered to be the dominant sources of Galactic cosmic rays. For a long time the prime evidence consisted of radio synchrotron radiation from supernova remnants, indicating the presence of electrons with energies of several GeV. However, in order to explain the cosmic ray energy density and spectrum in the Galaxy supernova remnant should use 10% of the explosion energy to accelerate particles, and about 99% of the accelerated particles should be protons and other atomic nuclei.Over the last decade a lot of progress has been made in providing evidence that supernova remnant can accelerate protons to very high energies. The evidence consists of, among others, X-ray synchrotron radiation from narrow regions close to supernova remnant shock fronts, indicating the presence of 10-100 TeV electrons, and providing evidence for amplified magnetic fields, gamma-ray emission from both young and mature supernova remnants. The high magnetic fields indicate that the condition for accelerating protons to >1015 eV are there, whereas the gamma-ray emission from some mature remnants indicate that protons have been accelerated.

Propagation of Ultra-High Energy Cosmic Rays in Extragalactic Magnetic Fields

Open Physics ◽  
2004 ◽  
Vol 2 (2) ◽  
Author(s):  
Tadeusz Wibig
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Cosmic Ray ◽  
High Energy ◽  
Source Model ◽  
Energy Spectra ◽  
Single Source ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
Open Question

AbstractIn this paper we will discuss the problem of Ultra High Energy Cosmic Rays (UHECR) and show that the idea of a Single Source Model established by Erlykin and Wolfendale (1997) to explain the features seen in cosmic ray energy spectra around the 1015 eV region can be successfully applied also for the much higher energies. The propagation of UHECR (of energies higher than 1019 eV) in extragalactic magnetic fields can no longer be described as a random walk (diffusion) process and the transition to rectilinear propagation gives a possible explanation for the so-called Greisen-Zatzepin-Kuzmin (GZK) cut-off which still remains an open question after almost 40 years. A transient “single source” located at a particular distance and producing UHECR for a finite time is the proposed solution.

scholarly journals NMDB@Home

2021 ◽  
pp. 7-12
Author(s):  
Maria Abunina ◽  
Rolf Bütikofer ◽  
Karl-Ludwig Klein ◽  
Monica Laurenza ◽  
David Ruffolo ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Space Weather ◽  
Cosmic Ray ◽  
Original Data ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Neutron Detectors ◽  
User Community ◽  
Large User

An overview on the presentations at the first virtual symposium on cosmic ray studies with neutron detectors is given. The meeting was held online in July 2020. Neutron detectors on ground are shown to provide significant contributions to research on interactions of galactic cosmic rays with magnetic fields in the Heliosphere and on the acceleration of energetic particles, as well as to a growing range of applications, including geophysics and space weather. The advent of easily accessible databases makes original data easily available to a large user community. The present overview outlines and introduces the more detailed articles contained in the proceedings.

scholarly journals The power spectrum of cosmic ray arrival directions

2015 ◽  
Vol 2 ◽  
pp. 45-49 ◽  
Author(s):  
M. Ahlers
Keyword(s):  
Numerical Methods ◽  
Cosmic Rays ◽  
Power Spectrum ◽  
Large Scale ◽  
Cosmic Ray ◽  
Direct Consequence ◽  
Small Scale ◽  
Ray Diffusion ◽  
Liouville’S Theorem ◽  
Arrival Directions

Abstract. Various experiments show that the arrival directions of multi-TeV cosmic rays show significant anisotropies at small angular scales. It was recently argued that this small scale structure may arise naturally by cosmic ray diffusion in a large-scale cosmic ray gradient in combination with deflections in local turbulent magnetic fields. We show via analytical and numerical methods that the non-trivial power spectrum in this setup is a direct consequence of Liouville's theorem and can be related to properties of relative diffusion.

Possible Influence of Large Structures of Coronal Magnetic Fields on the Propagation of Solar Cosmic Rays

1994 ◽  
Vol 144 ◽  
pp. 107-109 ◽  
Author(s):  
S. Fischer ◽  
M. Vandas ◽  
E. V. Vashenyuk
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Neutral Line ◽  
Cosmic Ray ◽  
Heliospheric Current Sheet ◽  
Solar Cosmic Rays ◽  
Large Structures ◽  
The Earth ◽  
Coronal Magnetic Fields

AbstractAn investigation of mutual positions of footpoints of the Earth in the solar corona and the heliospheric current sheet (for both relativistic and nonrelativistic solar cosmic ray events) has not revealed any apparent dependence of observed SCR increases on the coronal distance of footpoints from the neutral line.

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