TURBULENT DYNAMOS IN SPHERICAL SHELL SEGMENTS OF VARYING GEOMETRICAL EXTENT

摘要: We use three-dimensional direct numerical simulations of the helically forced magnetohydrodynamic equations in spherical shell segments order to study effects changes geometrical shape and size domain on growth saturation large-scale magnetic fields. inject kinetic energy along with helicity domains via helical forcing using Chandrasekhar-Kendall functions. take perfect conductor boundary conditions for field ensure that no escapes boundaries. find dynamo action giving rise fields at scales larger than characteristic scale forcing. The exceeds over dissipative timescales, similar seen earlier Cartesian periodic boxes. As we increase azimuthal direction, nonlinearly saturated organizes itself long-lived cellular structures aspect ratios close unity. These tile thus resulting very small longitudinally averaged large sizes. these are determined by smallest domain, which our is usually radial scale. also increasing meridional extent produces little qualitative change, except a marginal field. obtain qualitatively results ratios.