What sustains the solar magnetic cycle?
The Sun reverses its large-scale magnetic polarity approximately every 11 years. What sustains these reversals, and why is the period so much longer than the solar rotation period?
In a preprint submitted to Physical Review E, I derive exact non-linear magnetohydrodynamic solutions in a rotational shear flow. Circulation turns the poloidal field; shear generates the toroidal field; magnetic tension and Coriolis deflection alter the shear flow and circulation. This cycle supports a dynamo wave that reverses its magnetic components over many rotation periods. I also use anelastic MHD simulations in AthenaK to study sustained magnetic reversals and meridional circulation resembling solar observations. I am also developing a fully compressible low-Mach MHD solver for stratified magnetoconvection.
- Circulation turns the poloidal field.
- Shear stretches it into a toroidal field.
- Magnetic tension and Coriolis forces act back on the flow, continuing the cycle.
The analytical solution describes a dynamo wave in a shear flow; the anelastic MHD simulation follows magnetic reversals and circulation in a stratified, shearing solar box.
