We study the question of what dierence it makes for the derived ®eld-aligned conductance (K) values if one uses Maxwellian or kappa distributions for the ®tting of low-orbiting satellite electron ̄ux spectra in the auroral region. This question has arisen because sometimes a high-energy tail is seen in the spectra. In principle, the kappa ®ts should always be better, because the kappa distribu...