An ion manipulation device is disclosed comprising: an ion receiving region (30) for receiving ions; a pair of electrodes (14,16) adjacent the ion receiving region (30); and an AC or RF voltage supply (18) arranged to apply an AC or RF voltage to said electrodes (14,16), or arranged and configured to generate an electromagnetic field that couples to said electrodes (14,16) in use, such that an electromagnetic standing wave (24) is generated between said electrodes (14,16). A first of the electrodes (14) comprises one or more apertures through which an electric field from the standing wave (24) penetrates and enters the ion receiving region (30), in use, for urging said ions away from the one or more apertures.