diameter this energy goes into simple bulk heating of the fiber while the plasma and ultraviolet flux preferentially processes only the fiber 39 s surface to enhance the desorption of unwanted compounds by modulating the intensity of the plasma and the microwave radiation it is possible to produce an undulated surface on the reinforcement fiber depending upon the processing parameters this undulation can be tailored to a predetermined geometry more specifically the cross sectional diameter of the fiber may be modified along the length of the fiber by varying the intensity of the plasma and the microwave radiation as the fiber passes through the plasma and microwave field this feature both improves the ability of the fiber to mechanically interlock with composite resins and increases the surface area of the fiber to provide an increased number of sites for enhanced chemical binding and to allow further distribution of loads applied to the final composite material the combination of these effects ultimately produce a stronger bond between the fiber and the composite resin than could otherwise be obtained using conventional processes as shown in fig1 a 3 the undulated surface is characterized to include a continuous rolling topography of peaks and valleys on the fiber 39 s surface as compared to the generally linear topography of fibers treated with traditional low pressure plasma treatments fig4 or conventional.