IN RECENT years, surface dielectric barrier discharge (SDBD) plasma actuators, driven by alternating current (AC), have been a topic of great interest in the aerospace community. AC-SDBD plasma actuators are generally composed of two electrodes separated by a dielectric layer. The dielectric layer covers one electrode completely by insulating it, whereas the other electrode is uncovered and completely exposed to the air. Application of high voltage between the exposed and covered electrodes ionizes the air over the dielectric surface, producing plasma discharge over the covered electrode. This plasma discharge induces the adjacent air toward the actuator surface, producing downstream acceleration known as ionic wind (aerodynamic effect). This ionic wind of AC-SDBD plasma actuators is generally of several meters per second, and has been widely used for numerous aerodynamic flow control applications [1–8]. These actuators have tremendous advantages, including low mass, fast response time, robust nature, low consumption of power, and absence of moving mechanical parts [9]. In addition, these actuators can be conveniently arranged on the surface of the vehicle parts or the wind turbine. However, the drawback of plasma flow control is the low efficiency of energy conversion because the surface-discharge-induced kinetic power and electromechanical efficiency vs discharge is only several percent [10]. For an AC-SDBD plasma actuator, the induced aerodynamic effect only consumes a small part of the total electrical power, and the large part is converted into heat energy. Therefore, it has an obvious thermal effect. Recently, several researchers have investigated the thermal characteristics of AC-SDBD plasma actuators. Rakshit et al.[11] proposed the use of infrared (IR) thermography and emission spectroscopy techniques to measure thermal effects due to the plasma region’s high electric fields and the inability to employ intrusive techniques. Joussot et al.[12] studied the thermal characterization of an AC-SDBD actuator in still air and in the presence of external flow using steady plasma actuation, and revealed that turbulent boundary layer provides better heat dissipation than laminar. Rodrigues et al.[13] experimentally studied the total heat dissipation of an AC-SDBD actuator, and reported that the main dissipative region of thermal energy is in the plasma region. Stanfield and Menart [14] investigated the rotational temperature of the gas above the covered electrode using spectroscopy measurements of an AC-SDBD actuator. The results showed a decrease in the gas rotational temperature but an increase as the voltage increased. It is to be noted that all studies on the thermal behavior of AC-SDBD plasma only investigated steady actuation, and the unsteady thermal behavior is yet to be explored. In the recent years, the thermal characteristics of AC-SDBD actuators allowed them to use for heat transfer applications, such as film cooling of turbine blades [15, 16] and plasma icing control [17–19]. Meng et al.[20] proposed AC-SDBD actuators for icing control, and revealed that the coupling effect of plasma aerodynamic and thermal effect has a direct impact on icing results. However, only the results of the steady control were given and discussed in their study. To further reveal the detailed mechanism of coupling the aerodynamic and thermal effects of AC-SDBD plasma actuators, particle image velocimetry (PIV) and surface-temperature measurements are performed simultaneously in the present study. This study focuses on coupling the aerodynamic and thermal effects using both steady and unsteady actuation in static atmosphere. The …