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A plasma loop twisted Riemannian model is applied to torus dynamos twistedflows it leading to a slow dynamo such as in Moebius strip dynamo, recentlyconsidered by Shukurov, Stepanov and Sokoloff [Phys. Rev. \textbf{E78},025301,(2008)] to modelling Perm dynamo torus in liquid sodium. Sincediffusion and advection (stretching), are competing effects for dynamo action,plasma resistivity term is shown to be proportional to loops Riemann curvature(folding). Shukurov et al, also showed that based on Ponomarenko dynamo, abroader torus channel produces a better dynamo. These results agree withSchekochihin et al [Phys Rev \textbf{E} (2002)] where random filamentarymagnetic fields are strengthen by curvature. Analysis of spectrum of chaoticfast dynamos, shows that Riemann curvature acts as a damping, since growthmagnetic field rate is inversely proportional to Riemann curvature. Comparisonwith general relativistic MHD dynamo equation, shows that the Ricci tensor,which is a contraction of the Riemann tensor also appears in the diffusionterm. Curvature of plasma loop is${{R^{1}}_{212}}|_{\textbf{Plasma}}\approx{5.6{\times}10^{-19}m^{-2}}$, whilefor Perm torus is certainly higher. Thus slow dynamos are favoured in dynamolaboratories rather than in plasma loops. It is shown that thecurvature-stretching flux rope dynamo coupling energy, coincides with theminimum twist energy ${\epsilon}_{\textbf{twist}}\approx{10^{30}TeV}$ stored influx ropes. Torus flux tubes around black-holes remain in the order of $2MeV$and GBR are around $10^{52}TeV$. Since the ${R^{1}}_{212}$ is negative,inflexionary flux tubes fast dynamos may be responsible for this CME mechanismin UHF plasma loops.

Riemann curvature-stretching coupling in dynamo torus laboratory and in UHF twisted plasma loops