Magnetic curvature effects, investigated by Barrow and Tsagas (BT) [Phys Rev D \textbf{ 77},(2008)],as a mechanism for magnetic field decay in open Friedmann universes (${ \Lambda}<0$), are applied to dynamo geometric Ricci flows in 3D curved substrate in laboratory. By simple derivation, a covariant three-dimensional magnetic self-induced equation, presence of these curvature effects, indicates that de Sitter cosmological constant (${ \Lambda}\ge{ 0}$), leads to enhancement in the fast kinematic dynamo action which adds to stretching of plasma flows. From the magnetic growth rate, the strong shear case, anti-de Sitter case (${ \Lambda}<0$) BT magnetic decaying fields are possible while for weak shear, fast dynamos are possible. The self-induced equation in Ricci flows is similar to the equation derived by BT in $(3+1)$-spacetime continuum. Lyapunov-de Sitter metric is obtained from Ricci flow eigenvalue problem. In de Sitter analogue there is a decay rate of ${ \gamma}\approx{ -{ \Lambda}}\approx{ -10^{ -35}s^{ -2}}$ from corresponding cosmological constant ${ \Lambda}$, showing that, even in the dynamo case, magnetic field growth is slower than de Sitter inflation, which strongly supports to BT result.
Categories: gr-qc