this invention is an improved traveling wave ring resonator utilizing only one source of waves . the standard traveling wave ring resonator uses two wave sources phased 90 degrees apart and physically separated by a quarter wavelength to separately excite two equal - frequency standing wave modes which make up a traveling wave . the present invention uses perturbations of the ring resonator to shift the frequency of the standing wave modes , by specified amounts , and to correctly fix their position , to allow a single wave source to properly excite the standing wave modes which comprise a traveling wave . this invention has application to traveling wave ring resonators in acoustics , mechanical devices , and electromagnetic devices , as well as to simply - connected resonators to be excited in rotating wave modes . specific applications include improved thermoacoustic traveling wave heat engines and pumps , simplified surface wave motors , and energy efficient wave pools for recreational purposes .