Reconciling solar and stellar magnetic cycles with nonlinear dynamo simulations

Area of Science:

• Stellar astrophysics
• Plasma physics
• Heliophysics

Background:

• Solar-type stars display decadal magnetic field cycles, like the Sun's 11-year period.
• Stellar magnetic fields originate in turbulent convection zones and depend on rotation rate.

Purpose of the Study:

• To investigate the relationship between stellar rotation, luminosity, and magnetic cycle behavior.
• To understand the underlying dynamo processes governing stellar magnetic variability.

Main Methods:

• Performed global simulations of stellar turbulent convection.
• Systematically varied stellar rotation rate and luminosity in simulations.

Main Results:

• Magnetic cycle periods were found to vary systematically with stellar rotation and luminosity.
• A clear inverse relationship was observed between magnetic cycle period and the Rossby number.
• The findings support a nonlinear dynamo mechanism driving stellar magnetic cycles.

Conclusions:

• The Rossby number is a key parameter in determining stellar magnetic cycle lengths.
• The simulation results are consistent with observed solar and stellar magnetic cycles.
• This work provides insights into the fundamental physics of stellar magnetism.