| Abstract : | Magnetic fields are omnipresent in galaxies and galaxy clusters with different
field strengths and varying degree of orderedness. Random magnetic fields
in galaxies and galaxy clusters ordered on the scale of turbulent motions are
generated by Fluctuation dynamos. Due to their short amplification time
scales, these dynamos can rapidly amplify weak initial seed magnetic fields
to dynamically important strengths. The resulting fields are non-Gaussian
and spatially intermittent. Understanding the origin and evolution of these
fields and their observational signatures present an important challenge.
Despite spectacular progress over the last two decades, a comprehensive
understanding of the intricate issues associated with the dynamo process
still remains to be resolved. At the same time, to enable fruitful comparison
between theory and observations it is necessary to strengthen the theoretical
foundations by equipping it with predictive power, essential to plan for new
observations. In this light, drawing from the rich body of work on turbulent
dynamos, I will focus on two aspects of Fluctuation dynamos in this talk.
First, I will discuss some key issues in dynamo saturation and then I will
focus on how quantitative estimates of observational signatures obtained
from numerical simulations of Fluctuation dynamos in compressible
turbulence can be useful to probe magnetic fields in young galaxies and
galaxy clusters.
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