6–10 Apr 2009
Kiljavanranta Conference Centre, Finland
Europe/Stockholm timezone

The alpha effect with imposed and dynamo-generated magnetic fields

10 Apr 2009, 10:30
20m
Kiljavanranta Conference Centre, Finland

Kiljavanranta Conference Centre, Finland

Kiljavanranta, Kotorannantie 49, 05250 Kiljava, Finland,<br> tel. 09-276 251,<br> http://www.kiljavanranta.fi/in_english/

Speaker

Fabio Del Sordo (NORDITA)

Description

Estimates for the nonlinear alpha effect in helical turbulence are presented using two different approaches where a uniform magnetic field is applied either to the actual field, or where separate evolution equations are solved for a set of different test fields. Both approaches agree for stronger fields, but there are apparent discrepancies for weaker fields that can be explained by the influence of dynamo-generated meso-scale magnetic fields. Examples are discussed where with an imposed magnetic field the alpha effect is either drastically overestimated, or drastically underestimated compared with the kinematic value. It is demonstrated that the kinematic value can be estimated correctly by reseting the magnetic field in regular time intervals.

Primary author

Alexander Hubbard (Nordita)

Co-authors

Axel Brandenburg (Nordita) Fabio Del Sordo (NORDITA) Dr Petri Käpylä (University of Helsinki)

Presentation materials

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