Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

The precession dynamo experiment at HZDR

Giesecke, A.; Albrecht, T.; Gerbeth, G.; Gundrum, T.; Nore, C.; Stefani, F.; Steglich, C.

Most planets of the solar system are accompanied by a magnetic field with a large scale structure. These fields are generated by the dynamo effect, the process that provides for the transfer of kinetic energy from a flow of a conducting fluid into magnetic energy. In case of planetary dynamos it is generally assumed that these flows are driven by thermal and/or chemical convection but other driving sources like libration, tidal forcing or precession are possible as well. Precessional forcing, in particular, has been discussed since long as an at least additional power source for the geodynamo. A fluid flow of liquid sodium, solely driven by precession, will be the source for magnetic field generation in the next generation dynamo experiment currently under development at the Helmholz-Zentrum Dresden-Rossendorf (HZDR). In contrast to previous dynamo experiments no internal blades, propellers or complex systems of guiding tubes will be used for the optimization of the flow properties. However, in order to reach sufficiently high magnetic Reynolds numbers required for the onset of dynamo action rather large dimensions of the container are necessary making the construction of the experiment a challenge. At present state a small scale water experiment is running in order to estimate the hydrodynamic flow properties in dependence of precession angle and precession rate. The measurements are utilized in combination with numerical simulations of the hydrodynamic case as input data for kinematic simulations of the induction equation. The resulting growth rates and the corresponding critical magnetic Reynolds numbers will provide a restriction of the useful parameter regime and will allow an optimization of the experimental configuration.

Keywords: Dynamo; Precession

  • Poster
    AGU Fall Meeting, 09.-13.12.2013, San Francisco, USA
  • Open Access Logo Contribution to proceedings
    AGU Fall Meeting, 09.-13.12.2013, San Francisco, USA

Publ.-Id: 19315