The paper presents results of cold MHD flow deceleration experiments using repetitively pulsed, short pulse duration, high voltage discharge to produce ionization in a M=4 nitrogen flow in the presence of transverse DC electric field and transverse magnetic field. Effective flow conductivity is significantly higher than was previously achieved, σeff=0.1 S/m. MHD effect on the flow is detected from the flow static pressure measurements. Retarding Lorentz force applied to the flow produces a static pressure increase of 19%, while accelerating force of the same magnitude applied to the same flow results in static pressure increase of 11%. The effect is produced for two possible combinations of the magnetic field and transverse current directions producing the same Lorentz force direction (both for accelerating and retarding force). The results of static pressure measurements are compared with predictions of a 3-D Navier-Stokes / MHD flow code. The static pressure rise predicted by the code, 18% for the retarding force and 8% for the accelerating force, agrees well with the experimental measurements. Analysis of the calculations results shows that at the present conditions, the effects of Joule heating and the accelerating Lorentz force cancel each other, producing nearly zero net flow velocity change. On the other hand, the two effects are combined for the retarding Lorentz force, which results in approximately 2% flow velocity reduction, by Δu=15 m/sec. This result provides further evidence of cold supersonic flow deceleration by Lorentz force. Copyright ®, American Institute of Aeronautics and Astronautics. All rights reserved.