Dynamo effect in decaying helical turbulence

by A. Brandenburg, T. Kahniashvili, Mandal, S., Roper Pol, A., Tevzadze, A. G., & Vachaspati, T.

Reference:

  • Brandenburg, A., Kahniashvili, T., Mandal, S., Roper Pol, A., Tevzadze, A. G., & Vachaspati, T.: 2019, ``Dynamo effect in decaying helical turbulence,'' Phys. Rev. Fluids, 4, 024608 (arXiv:1710.01628, ADS, DOI, PDF, PDF)

    Run directories:

    The following links contain the original run directories with secondary data such as time series and spectra. The full snapshots are not stored, but all the relevant files needed for rerunning any particular simulation exist. In each directory, the input files (*.in) exist and data are under the directory data (including time series and spectra). In some cases, data directly relevant for particular plots are available, for example the directory "spectra" contains selected spectra used in some plots.

  • Figs. 1-5, 7-12: Run A
  • Figs. 1+2, 7: Run B
  • Figs. 1+2, 6+7: Run C
  • Figs. 1+2: Run D
  • Figs. 1+2: Run E
  • Fig. 1: Run E'
  • Fig. 10: Run F
  • Fig. 10: Run G
  • Fig. 10: Run H
  • Fig. 13: PrM=0.1, PrM=10
  • Fig. 14: ν=η=10-6 run,

    The following figure shows the evolution of the normalized cross helicity for Run A. It varies between 0.15 and 0.2%. This is small and therefore probably consistent with zero.


    For Run A, the data for the spectra shown in the figure below (Fig.3 of the paper) are given here. Example: the last times (fat lines) correspond to last number, which is 7, so EM_7.txt contains the magnetic energy, normalized as shown in the figure. From the figure, we expect to find the maximum at k/k0=0.07. This is indeed the case, and we see in the table that: 
        0.0500000  9.83119e-06
    0.0666667  1.15122e-05
    0.0833333  6.04016e-06
    in lines 4-6. The value 1.15122e-05 agrees with what is shown in the figure. For the kinetic energy at the first time, we expect the maximum at around unity and see in the neighborhood 
         0.933333   0.00100515
     0.950000   0.00104804
     0.966667   0.00102022
    which also agrees with the figure. For each file, the times in units of tau0 is given at the end of the first line. Another example is here for the ν=η=10-6 run.



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    Axel Brandenburg
    $Date: 2020/10/10 17:17:16 $, $Author: brandenb $, $Revision: 1.5 $