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Plasma control of forebody asymmetric vortices is mostly achieved by means of dielectric barrier discharge (DBD) plasma actuators. However, DBD actuators suffer from some disadvantages such as a weak induced body force, a single-direction induced jet, and an unclear control mechanism. We carry out wind tunnel experiments involving the forebody vortex control of a slender body at high angles of attack using an innovative extended DBD actuator, which has a stronger capacity to induce an electric wind than a DBD actuator. Through synchronous measurements of the pressure distribution and particle image velocimetry (PIV), the spatiotemporal evolution of the dynamic interactions between plasma-actuation-induced vortices and forebody asymmetric vortices is analyzed. The influence of plasma discharge on the boundary layer separation around a slender body and the spatial topological structures of asymmetric vortices are further surveyed, as the optimized actuation parameters. Extended DBD actuators are found to be more capable of controlling asymmetric vortices than DBD actuators, and a linear proportionality of the sectional lateral force versus the duty ratio is achieved. There exists an optimal normalized reduced frequency ( f+=2πfpd/U∞=2.39) for asymmetric vortex control under the present experimental conditions. The research results can provide technical guidance for the control and reuse of forebody asymmetric vortices.