Ion saturation currents in a Hanbit mirror plasma have been analyzed by using the wavelet bispectral method. From this bicoherence analysis, an interesting phase coherent mode has been found at a very low frequency. This mode seems to be generated by the low frequency turbulence which could be identified as either ion drift waves or interchange modes. The wave coupling process leading to this coherent structure is found to follow the resonant three-wave coupling with an exact frequency match. A brief review is given on this coherent turbulence structure in a Hanbit mirror plasma.