Title: Three-dimensional oscillatory magnetic reconnection,
Abstract: Here we detail the dynamic evolution of localised reconnection regions about
three-dimensional (3D) magnetic null points by using numerical simulation. We
demonstrate for the first time that reconnection triggered by the localised
collapse of a 3D null point due to an external MHD wave involves a
self-generated oscillation, whereby the current sheet and outflow jets undergo
a reconnection reversal process during which back-pressure formation at the jet
heads acts to prise open the collapsed field before overshooting the
equilibrium into an opposite-polarity configuration. The discovery that
reconnection at fully 3D nulls can proceed naturally in a time-dependent and
periodic fashion is suggestive that oscillatory reconnection mechanisms may
play a role in explaining periodicity in astrophysical phenomena associated
with magnetic reconnection, such as the observed quasi-periodicity of solar and
stellar flare emission. Furthermore, we find a consequence of oscillatory
reconnection is the generation of a plethora of freely-propagating MHD waves
which escape the vicinity of the reconnection region