The invention relates to the field of magnetohydrodynamic generators, and more specifically to such a generator (10) including a flow duct (11) for a working fluid, delimited by a first wall (12) and a second wall (13), a working fluid ionization device (14), a pair of arms (15), each connecting the first and second walls (12, 13) downstream of said ionization device (14) so as to define, between said arms (15) and said walls (12, 13), a channel (16) in the flow duct (11), said channel (16) being arranged so as to have some of the working fluid passing therethrough after the ionization thereof, a magnet for generating a magnetic field (B) oriented perpendicularly to the flow of the working fluid in the channel (16) delimited by the pair of arms (15) and said walls (12, 13), and at least one pair of electrodes (17). Each electrode (17) of each pair is arranged on one side of the channel (16) delimited by the pair of arms (15) and said walls (12, 13). Said electrodes (17) of each pair are spaced apart from one another perpendicularly to said magnetic field (B) and the flow of the working fluid in the channel (16) delimited by the pair of arms (15) and said walls (12, 13).