The first direct experimental measurements of electron current due to rotating spokes in a modern highpower Hall thruster are presented. A segmented anode consisting of 12 equally spaced azimuthal sections has been retrofitted onto the H6 6-kW class Hall thruster and operated at power levels up to 3 kilowatts. Independent discharge current measurements on each anode segment at 1 MHz and synchronous high-speed video of the discharge at 87,500 frames per second reveal that visible rotating spoke structures in the thruster channel correspond to local electron current oscillations with amplitude approximately 30% of the mean local discharge current through each segment. Discrete Fourier transforms of discharge current oscillations on each segment reveal peaks at spoke rotation frequencies an order of magnitude larger than at the well-known breathing mode frequency. The apparent dominance of the breathing mode in traditional Hall thruster discharge current frequency spectra is revealed to be an artifact of the use of a contiguous ring-shaped anode. Based on the magnitude of local discharge current oscillations on each segment, the magnitude of plasma density oscillations are inferred to be of the order of the mean plasma density and the net discharge current carried by the spoke mechanism is calculated to be up to 50% of the total thruster discharge current. Nomenclature B= applied magnetic field b = azimuthal video bin index δ = phase shift between density and electric field perturbations E z = applied axial electric field = ratio of n /n 0 E θ = induced azimuthal electric field f m = spoke frequency of the m th spoke mode i = pixel column index j ez = mean axial electron current density j ez = axial electron current density oscillation amplitude j = pixel row index j ez = axial electron current density k = video frame index k θ = rotating spoke wave number λ = rotating spoke wavelength M = mean video image m = rotating spoke mode number n = plasma density perturbation amplitude n 0 = mean plasma densitȳ p = azimuthal bin mean pixel brightness p norm AC = normalized and AC-coupled azimuthal bin mean pixel brightness p norm = normalized azimuthal bin mean pixel brightness p = pixel brightness q = electron charge R = mean discharge channel radius * Doctoral Candidate, University of Michigan, Applied Physics Program. msmcdon@umich.edu. Student Member AIAA. r = radial thruster coordinate θ = azimuthal coordinate in Hall thruster channel θ b = azimuthal bin for video processing v ez = axial electron velocity v m = linear velocity of the m th spoke mode X k = normalizing factor for k th video frame X t = normalizing factor for discharge current at time t z = axial thruster coordinate