  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.
