scholarly journals Numerical simulations of local thundercloud field enhancements caused by runaway avalanches seeded by cosmic rays and their role in lightning initiation

2012 ◽  
Vol 117 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Leonid P. Babich ◽  
Evgeniĭ I. Bochkov ◽  
Joseph R. Dwyer ◽  
Igor M. Kutsyk
Keyword(s):  
Cosmic Rays ◽  
Numerical Simulations ◽  
Lightning Initiation ◽  
Field Enhancements

scholarly journals Impact of solar magnetic field amplitude and geometry on cosmic rays diffusion coefficients in the inner heliosphere

2020 ◽  
Vol 10 ◽  
pp. 55
Author(s):  
Barbara Perri ◽  
Allan Sacha Brun ◽  
Antoine Strugarek ◽  
Victor Réville
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Cosmic Rays ◽  
Numerical Simulations ◽  
Transport Equation ◽  
Diffusion Coefficients ◽  
Galactic Cosmic Rays ◽  
Current Sheets ◽  
The Magnetic Field ◽  
Inner Heliosphere

Cosmic rays are remarkable tracers of solar events when they are associated with solar flares, but also galactic events such as supernova remnants when they come from outside our solar system. Solar Energetic Particles (SEPs) are correlated with the 11-year solar cycle while Galactic Cosmic Rays (GCRs) are anti-correlated due to their interaction with the heliospheric magnetic field and the solar wind. Our aim is to quantify separately the impact of the amplitude and the geometry of the magnetic field, both evolving during the solar cycle, on the propagation of cosmic rays of various energies in the inner heliosphere (within Earth orbit). We focus especially on the diffusion caused by the magnetic field along and across the field lines. To do so, we use the results of 3D magnetohydrodynamics (MHD) wind simulations running from the lower corona up to 1 AU. This gives us the structure of the wind and the corresponding magnetic field. The wind is modeled using a polytropic approximation, and fits and power laws are used to account for the turbulence. Using these results, we compute the parallel and perpendicular diffusion coefficients of the Parker cosmic ray transport equation, yielding 3D maps of the diffusion of cosmic rays in the inner heliosphere. By varying the amplitude of the magnetic field, we change the amplitude of the diffusion by the same factor, and the radial gradients by changing the spread of the current sheet. By varying the geometry of the magnetic field, we change the latitudinal gradients of diffusion by changing the position of the current sheets. By varying the energy, we show that the distribution of values for SEPs is more peaked than GCRs. For realistic solar configurations, we show that diffusion is highly non-axisymmetric due to the configuration of the current sheets, and that the distribution varies a lot with the distance to the Sun with a drift of the peak value. This study shows that numerical simulations, combined with theory, can help quantify better the influence of the various magnetic field parameters on the propagation of cosmic rays. This study is a first step towards the resolution of the complete Parker transport equation to generate synthetic cosmic rays rates from numerical simulations.

scholarly journals Magnetic fields and cosmic rays in galaxy clusters and large scale structures

2008 ◽  
Vol 4 (S259) ◽  
pp. 519-528 ◽  
Author(s):  
Klaus Dolag ◽  
F. Stasyszyn ◽  
J. Donnert ◽  
R. Pakmor
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Numerical Simulations ◽  
Galaxy Clusters ◽  
Large Scale ◽  
High Energy ◽  
Transport Processes ◽  
Origin And Evolution ◽  
Large Scale Structures ◽  
High Energy Particles

AbstractIn galaxy clusters, non-thermal components such as magnetic field and high energy particles keep a record of the processes acting since early times till now. These components play key roles by controlling transport processes inside the cluster atmosphere and beyond and therefore have to be understood in detail by means of numerical simulations. The complexity of the intra cluster medium revealed by multi-frequency observations demonstrates that a variety of physical processes are in action and must be included properly to produce accurate and realistic models. Confronting the predictions of numerical simulations with observations allows us to validate different scenarios about origin and evolution of large scale magnetic fields and to investigate their role in transport and acceleration processes of cosmic rays.

scholarly journals Magnetic Fields and Cosmic Rays in Galaxy Clusters

2009 ◽  
Vol 5 (H15) ◽  
pp. 461-463 ◽  
Author(s):  
Klaus Dolag
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Numerical Simulations ◽  
Galaxy Clusters ◽  
Large Scale ◽  
High Energy ◽  
Transport Processes ◽  
Physical Processes ◽  
Origin And Evolution ◽  
High Energy Particles

AbstractIn galaxy clusters, non-thermal components such as magnetic field and high energy particles keep a record of the processes acting since early times till now. These components play key roles by controlling transport processes inside the cluster atmosphere and beyond and therefore have to be understood in detail by means of numerical simulations. The complexity of the intra cluster medium revealed by multi-frequency observations demonstrates that a variety of physical processes are in action and must be included properly to produce accurate and realistic models. Confronting the predictions of numerical simulations with observations allows us to validate different scenarios about origin and evolution of large scale magnetic fields and to investigate their role in transport and acceleration processes of cosmic rays.

Shielding Space Explorers From Cosmic Rays

Space Weather ◽  
2005 ◽  
Vol 3 (8) ◽  
pp. n/a-n/a ◽  
Author(s):  
Eugene N. Parker
Keyword(s):  
Cosmic Rays
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