Canvi de data [SEMINARI] Cosmic-Ray driven dynamo in galactic disks

[Enric Marco]

Title: Cosmic-Ray driven dynamo in galactic disks

By: Michal Hanasz

From: Centre for Astronomy, Nicolaus Copernicus University, Torun, Polònia

Seminari del departament d'Astronomia i Astrofísica

Dijous 24 juny 2010

12:00

Resum

I am going to present recent developments of local and global, 
galactic-scale numerical models, of the Cosmic-Ray driven dynamo, which 
was originally proposed by Parker (1992). We conduct global, 
galactic-scale CR-MHD numerical simulations of the dynamics of 
interstellar medium, composed of gas, magnetic-field, and cosmic-ray 
components. We take into account cosmic rays, accelerated in randomly 
distributed supernova remnants, and assume that supernovae deposit 
small-scale, randomly oriented, dipolar magnetic-fields into the ISM. We 
find that, the magnetization of galactic disks by exploding magnetized 
stars forms a favorable initial condition for the galactic dynamo 
process. The amplification timescale of the large-scale magnetic field, 
resulting from the CR-driven dynamo, is comparable to the galactic 
rotation period. The process converts efficiently small-scale magnetic 
fields of SN-remnants into the galactic-scale magnetic fields. The 
resulting magnetic-field structure resembles the observed X-shaped 
magnetic fields in edge-on galaxies.

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/------------------------------------\
 Dr. Enric Marco
 Departament d'Astronomia i Astrofísica
 Facultat de Física
 Universitat de València
 C/  Dr. Moliner, 50
 46100 Burjassot, Spain
 Phone: (34)-96-354-3069
 Fax:(34)-96-354-3084
 enric.marco en uv.es
 http://www.uv.es/marco
 http://www.uv.es/aulaastronomia
 http://www.uv.es/daa
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