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ABSTRACTThe results of the present work demonstrate the Lorentz force effect on the supersonic boundary layer in M = 3 flows of nitrogen ionized by a transverse RF discharge in the presence of the magnetic field. Boundary layer density fluctuation spectra are measured using the Laser Differential Interferometry (LDI) diagnostics. In particular, decelerating Lorentz force applied to the flow produces a well reproduced increase of the density fluctuation intensity by up to 10-20% (1-2 dB), compared to the accelerating force of the same magnitude applied to the same flow. The effect is produced for two possible combinations of the magnetic field and MHD current directions producing the same Lorentz force direction (both for accelerating and decelerating force). The effect is observed to increase with the flow conductivity. A new blowdown nonequilibrium plasma MHD supersonic wind tunnel operated at complete steady state has been developed and tested at Ohio State. The wind tunnel can be operated at Mach numbers up to M=3-4, and mass flow rates of up to 45 g/sec at a stagnation pressure of 1 atm. Pitot tube and schlieren measurements in a M=3 test section showed reasonably good flow quality, up to 80% inviscid core across the larger dimension and up to 50% inviscid core across the smaller dimension of the flow. Stable and diffuse transverse RF discharges (RF power up to I kW) have been sustained in M=3 nitrogen flows, at magnetic fields of up to B=1.5 T. Operation at higher magnetic fields produced a more uniform RF plasma in the MHD test section. The results of the present work demonstrate the Lorentz force effect on the supersonic boundary layer in M=3 flows of nitrogen ionized by a transverse RF discharge in the presence of the magnetic field. Boundary layer density fluctuation spectra are measured using the Laser Differential Interferometry (LDI) diagnostics. In particular, decelerating Lorentz force applied to the flow produces a well reproduced increase of the density fluctuation intensity by up to 10-20% (1-2 dB), compared to the accelerating force of the same magnitude applied to the same flow. The effect is produced for two possible combinations of the magnetic field and MHD current directions producing ...