The linear ion gyro-kinetic equation in stellarator geometry is presen
ted. This equation, together with the quasineutrality condition and an
adiabatic electron response, is solved as an initial-value problem al
ong the magnetic field line. Numerical results for the toroidal heliac
H1-NF (Hamberger S M et al 1990 Fusion Technol. 17 123) are presented
. It is shown that the local properties of the confining magnetic fiel
d, such as the normal and geodesic curvatures and the integrated resid
ual shear, are important for the mode localization along the field lin
e.