[Abstract] Thi s work focuses upon the effects of DC electric fields on the stability of downward propagating, atmospheric - pressure pre - mixed propane - air flames under experimental conditions that provide close coupling of the electric field to the flame. With the approp riate electrode geometry, modest applied voltages are shown to force pre - mixed light hydrocarbon/air flame fronts to transition from flow - induced hydrodynamic - instability - dominated behavior, to field stabilized laminar flow, and finally to field - induced th ermal - diffusive - instability - dominated oscillatory and turbulent flame. Applied potentials up through 5.5 kV over a 40 - mm gap encompassing the flame front have been used to force that transition sequence in flames with equivalence ratios between 0.8 – 1.3 and flow velocities up to 1.9 m/s. Experiments are reported that characterize the field - induced changes in the geometry of the reaction zone and the stability of the resulting turbulized flame. The former is quantified by combustion intensity enhancement estimates derived from high - speed two - dimensional direct and spectroscopic imaging of chemi - luminescence. The flame fluid mechanical response to the applied field, brought about by forcing positive flame ions counter to the flow, drives the effective fla me Lewis number below unity and on to levels below the critical value for the onset of the thermodiffusive instability, even near stoichiometric conditions. Possible field - driven flame ion recombination chemistry that would inject light reactants near the burner head and precipitate the onset of the thermodiffusive instability is proposed. Electrical measurements are also reported which establish that minimal electrical power input is required to produce the observed flame instabilities. Current - continui ty - based calculations allow estimates of the level of deficient light reactant necessary to turbulize the flame. This applied - electric - field induced modification of the thermodiffusive effect could serve as a potentially attractive means of controlling fl ame fluid mechanical characteristics and validating combustion instability models over a wide range of equivalence ratios. Measurements further suggest that electrical sensing of the onset of combustion instability should be feasible.