Dynamos with wind

• Applicants: Dr. Detlef Elstner; Professor Dr. Harald Lesch
• Subject Area: Astrophysics and Astronomy
• Term: from 2010 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 108727618

• Final Report Year: 2017

Final Report Abstract

The box simulations of the ISM lead to a full non-linear description of the mean field dynamo in dependence on the local properties like rotation, density and star formation. The saturation mechanism of the dynamo by a wind could be identified. With this complete description of the local dynamo process a sub-grid model for global disk galaxies could be developed. The results mark an important step on which derived mean-field models rely to explain observed equipartition-strength fields. The inclusion of cosmic rays with a diffusion-advection description did not significantly change the growth rate of the dynamo, but the properties of the turbulence became more anisotropic. Under the assumption of equipartition between cosmic rays and magnetic field it was shown by analytic considerations and supported by a global disk simulation, that the effect of the Lorentz force on the gas rotation is rather limited and will not explain a flat rotation curve with the observable matter distribution. This is also supported by recent LOFAR measurements of the synchrotron scale length. The implementation of turbulence properties as sub-grid model in SPMHD is completed. In this connection also a new algorithm using the vector potential for the magnetic field could improve the accuracy of the method by fullfilling its solenoidality.

Publications

• MNRAS, 429, L60
  Beck, A. M., Hanasz, M., Lesch, H., Remus, R.-S., Stasyszyn, F. A.
  (See online at https://doi.org/10.1093/mnrasl/sls026)
• 2013, MNRAS, 428, 13
  Stasyszyn, F. A., Dolag, K., Beck, A. M.
  (See online at https://doi.org/10.1093/mnras/sts018)
• 2013, MNRAS, 429, 967
  Gressel, O., Bendre, A., Elstner, D.
  (See online at https://doi.org/10.1093/mnras/sts356)
• 2013, MNRAS, 435, 3575
  Beck, A.M., Dolag, K., Lesch, H., Kronberg, P.P.
  (See online at https://doi.org/10.1093/mnras/stt1549)
• 2014, A&A, 568, 104
  Elstner, D., Beck, R., Gressel, O.
  (See online at https://doi.org/10.1051/0004-6361/201423960)
• 2014, MNRAS, 443, 3107
  Lacerna, I., Padilla, N., Stasyszyn, F.
  (See online at https://doi.org/10.1093/mnras/stu1318)
• 2015, AN, 336, 991
  Bendre, A., Gressel, O., Elstner, D.
  (See online at https://doi.org/10.1002/asna.201512211)
• 2015, CoPh, 282, 148
  Stasyszyn, F.A., Elstner, D.
  (See online at https://doi.org/10.1016/j.jcp.2014.11.011)
• 2016, JCAP, 056
  Beck, M.C., Beck, A.M., Beck, R., Dolag, K. et al.
  (See online at https://doi.org/10.1088/1475-7516/2016/05/056)
• 2016, MNRAS, 455, 1989
  Goicovic, F. G., Cuadra, J., Sesana, A., Stasyszyn, F., Amaro-Seoane, P., Tanaka, T. L.
  (See online at https://doi.org/10.1093/mnras/stv2470)