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Context: MHD waves and magnetic null points are both prevalent in manyastrophysical plasmas, including the solar atmosphere. Interaction betweenwaves and null points has been implicated as a possible mechanism for localisedheating events. Aims: Here we investigate the transient behaviour of the Alfvenwave about fully 3D proper and improper 3D magnetic null points. Previously,the behaviour of fast magnetoacoustic waves at null points in 3D, cold MHD wasconsidered by Thurgood & McLaughlin (Astronomy & Astrophysics, 2012, 545, A9).Methods: We introduce an Alfven wave into the vicinity of both proper andimproper null points by numerically solving the ideal, $\beta=0$ MHD equationsusing the LARE3D code. A magnetic fieldline and flux-based coordinate systempermits the isolation of resulting wave-modes and the analysis of theirinteraction. Results: We find that the Alfven wave propagates throughout theregion and accumulates near the fan-plane, causing current build up. Fordifferent values of null point eccentricity, the qualitative behaviour changesonly by the imposition of anisotropic pulse dilation, due to the differingrates at which fieldlines diverge from the spine. For all eccentricities, wefind that the fast and Alfven waves are linearly decoupled. During the drivingphase, an independently propagating fast wave is nonlinearly generated due tothe ponderomotive force. Subsequently, no further excitation of fast wavesoccurs. Conclusions: We find that the key aspects of the theory of Alfv\'enwaves about 2D null points extends intuitively to the fully 3D case; i.e. thewave propagates along fieldlines and thus accumulates at predictable parts ofthe topology. We also highlight that unlike in the 2D case, in 3D Alfven-wavepulses are always toroidal and thus any aspects of 2D Alfven-wave-null modelsthat are pulse-geometry specific must be reconsidered in 3D.

3D Alfven wave behaviour around proper and improper magnetic null points