This paper reports on the high-field electrical transport properties of metallic single-wall carbon nanotubes (SWNTs). Using low-resistance contacts, the authors measured the intrinsic transport characteristics of individual SWNTs, finding that they can carry currents with a density exceeding 10^9 A/cm². As the bias voltage increases, the conductance drops due to electron scattering. The current-voltage characteristics are explained by considering optical or zone-boundary phonon emission as the dominant scattering mechanism at high fields. The study shows that SWNTs can sustain high current densities due to their one-dimensional nature and unique electronic properties. The authors developed an analytic theory based on the Boltzmann equation to model the transport behavior, including both elastic scattering and phonon emission. The numerical calculations reproduce the experimental results well. The paper discusses the transport mechanisms in SWNTs, focusing on whether electrons travel ballistically or are scattered by impurities or phonons. The unusual band structure of metallic tubes suggests a suppression of elastic backscattering by long-range disorder. The authors also investigate the effect of backscattering in the nanotube, considering phonon emission as a dominant scattering mechanism. The results show that the resistance can be fit by a linear function of voltage, with a saturation current independent of the electrode spacing. The authors propose that the saturation current is due to phonon emission, with the mfp for backscattering phonons scaling inversely with voltage. The study also discusses the implications of the transport behavior for potential electronic applications of SWNTs.This paper reports on the high-field electrical transport properties of metallic single-wall carbon nanotubes (SWNTs). Using low-resistance contacts, the authors measured the intrinsic transport characteristics of individual SWNTs, finding that they can carry currents with a density exceeding 10^9 A/cm². As the bias voltage increases, the conductance drops due to electron scattering. The current-voltage characteristics are explained by considering optical or zone-boundary phonon emission as the dominant scattering mechanism at high fields. The study shows that SWNTs can sustain high current densities due to their one-dimensional nature and unique electronic properties. The authors developed an analytic theory based on the Boltzmann equation to model the transport behavior, including both elastic scattering and phonon emission. The numerical calculations reproduce the experimental results well. The paper discusses the transport mechanisms in SWNTs, focusing on whether electrons travel ballistically or are scattered by impurities or phonons. The unusual band structure of metallic tubes suggests a suppression of elastic backscattering by long-range disorder. The authors also investigate the effect of backscattering in the nanotube, considering phonon emission as a dominant scattering mechanism. The results show that the resistance can be fit by a linear function of voltage, with a saturation current independent of the electrode spacing. The authors propose that the saturation current is due to phonon emission, with the mfp for backscattering phonons scaling inversely with voltage. The study also discusses the implications of the transport behavior for potential electronic applications of SWNTs.