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The influence of the finite ionospheric\udconductivity on the structure of dispersive, nonradiative field line resonances\ud(FLRs) is investigated for the first four odd harmonics. The results are based\udon a linear, magnetically incompressible, reduced, two-fluid MHD model. The\udmodel includes effects of finite electron inertia (at low altitude) and finite\udelectron pressure (at high altitude). The ionosphere is treated as a\udhigh-integrated conducting substrate. The results show that even very low\udionospheric conductivity (ΣP = 2 mho) is not\udsufficient to prevent the formation of a large-amplitude, small-scale,\udnonradiative FLR for the third and higher harmonics when the background\udtransverse plasma inhomogeneity is strong enough. At the same time, the\udfundamental FLR is strongly affected by a state of low conductivity, and when\udΣP = 2 mho, this resonance forms only\udsmall-amplitude, relatively broad electromagnetic disturbance. The difference in\udconductivities of northern and southern ionospheres does not produce significant\udasymmetry in the distribution of electric and magnetic fields along the resonant\udfield line. The transverse gradient of the background Alfvén speed plays an\udimportant role in structure of the FLR when the ionospheric conductivity is\udfinite. In cases where the transverse inhomogeneity of the plasma is not strong\udenough, the low ionospheric conductivity can prevent even higher-harmonic FLRs\udfrom contracting to small scales where dispersive effects are important. The\udapplication of these results to the formation and temporal evolution of\udsmall-scale, active auroral arc forms is discussed

Influence of the finite ionospheric conductivity on dispersive, nonradiative field line resonances