Particle simulations are employed in a self-consistent investigation of the growth and saturation of current-driven instabilities along auroral field lines. Ion cyclotron waves are found to grow to levels eϕ/Te~0.2--0.4, which are comparable with the levels observed by the S3-3 satellite. In the present initial-value calculations, saturation is due to plateau formation on the electron distribution function. Excitation of the ion cyclotron waves leads to moderate (~40%) perpendicular heating of the ions but does not produce a high-energy tail. The associated anomalous resistivity is relativity small, &ngr;*/&ohgr;pe~1¿10-4. Implications of these results for observation of ion cyclotron waves on auroral field lines are discussed.