Large-scale magnetic field saturation and the Elsasser number in rotating spherical dynamo models Journal Article uri icon



  • ABSTRACT; Numerical simulations are used to investigate large-scale (mean) magnetic field generation in rotating spherical dynamos. Beyond a certain threshold, we find that the magnitude of the mean magnetic field becomes nearly independent of the system rotation rate and buoyancy forcing. The analysis suggests that this saturation arises from the Malkus-Proctor mechanism in which a Coriolis-Lorentz force balance is achieved in the zonal component of the mean momentum equation. When based on the large-scale magnetic field, the Elsasser number is near unity in the saturated regime. The results show that the large and small magnetic field saturate via distinct mechanisms in rapidly rotating dynamos, and that only the axisymmetric component of the magnetic field appears to follow an Elsasser number scaling.

publication date

  • September 7, 2021

Date in CU Experts

  • August 16, 2021 11:54 AM

Full Author List

  • Orvedahl RJ; Featherstone NA; Calkins MA

author count

  • 3

Other Profiles

International Standard Serial Number (ISSN)

  • 1745-3925

Electronic International Standard Serial Number (EISSN)

  • 1745-3933

Additional Document Info

start page

  • L67

end page

  • L71


  • 507


  • 1