We investigate the separated flow around an inclined flat plate at a Reynolds number of 10⁴ by Direct Numerical Simulation (DNS) and time-resolved Particle Image Velocity (PIV). Flow separation is suppressed using sinusoidally and rectangularly oscillating Lorentz forces in streamwise direction. An rms momentum coefficient of 2.25% increases the time-averaged lift, deduced from PIV by a global momentum approach, by 20-45%. Whereas sinusoidal forcing increases both lift and drag, rectangular waves create no significant additional drag. Analysis of the DNS flow structures reveals different immediate vortex dynamics induced by the actuation.