Dynamo Simulations of Planetary Cores

Ryan Orvedahl, UC Davis

The majority of solar system planets possess global, or large-scale, magnetic fields. These magnetic fields are all thought to be generated by the dynamo mechanism, whereby kinetic energy associated with a convectively stirred plasma is converted into electromagnetic energy. Most planets have a large-scale magnetic field that is aligned with its rotation axis and often are characterized by a relatively strong dipolar component. In this work, large-scale magnetic field properties are investigated using rapidly rotating numerical simulations in a sphere. The large-scale magnetic field saturates as the intensity of convective motions is increased. The saturation is explored over a wide range of system parameters and is found to be a robust feature of rapidly rotating dynamo simulations. These results are described using a semi-magnetostrophic force balance, where the Lorentz force enters the leading-order mean force balance in only a single component direction. These simulations are generated using the Rayleigh pseudo-spectral code and current software development plans for its improvement will also be discussed.

[register]