It is well know that normal curvature can have destabilizing effects on plasma turbulence. However, also the geodesic curvature seems to be important. 

relevant publications

G. Birkenmeier et al.'Experimental Investigation of the Magnetic Configuration Dependence of Turbulent Transport' Phys. Rev. Lett. 107, 025001 (2011)

S Garland, P Manz, M Ramisch 'The influence of magnetic field curvature on intermittency in drift-wave turbulence in the stellarator TJ-K' Physics of Plasmas 27, 052304 (2020)