[SEMINARI] Cosmic-Ray driven dynamo in galactic disks, Michal Hanasz

[Enric Marco]

Cosmic-Ray driven dynamo in galactic disks

Michal Hanasz
Centre for Astronomy, Nicolaus Copernicus University,
Torun, Poland

Dia: Dimecres 23 juny 2010
Hora: 12:00
Lloc: Seminari d'Astronomia i Astrofísica


Abstract

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
www.uv.es/marco
www.uv.es/aia2009
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