Abstract Recently, there has been increased interest in using atmospheric pressure plasmas for materials processing, since these plasmas do not require expensive vacuum systems. However, APGDs face instabilities. Therefore, special plasma sources have been developed to overcome this obstacle, which make use of DC, pulsed DC and AC ranging from mains frequency to RF. Recently, the APPJ was introduced, which features an α ‐mode of an RF discharge between two bare metallic electrodes. Basically, three different geometric configurations have been developed. A characterization of the APPJs and their applications is presented. magnified image
Summary form only given. Plasma arc cutting is a widely used method for cutting metals. The availability of small portable units using compressed air as plasma gas makes these devices suitable for use in workshops. However, the need for compressed air means less flexibility in field applications. Possible solution strategies to overcome this disadvantage are the integration of the air supply on board or the production of plasma gas in situ. A plasma cutting device using the latter concept is presented. In order to achieve good cutting quality the plasma jet needs high enthalpy to melt the workpiece and high momentum to blow away the liquid metal. The nozzle which confines the plasma jet is usually either cooled by air or at higher power levels by water. This excess of heat, however, can be used to produce the necessary plasma gas within the plasma torch by vaporization of a fluid (e.g. water). This kind of cooling is also known as regenerative cooling. The main aspect of the process is the thermal management of the torch.
