  Oscillatory reconnection is a process that has been suggested to underlie
several solar and stellar phenomena, and is likely to play an important role in
transient events such as flares. Quasi-periodic pulsations (QPPs) in flare
emissions may be a manifestation of oscillatory reconnection, but the
underlying mechanisms remain uncertain. In this paper, we present 2D
magnetohydrodynamic (MHD) simulations of two current-carrying magnetic flux
ropes with an out-of-plane magnetic field undergoing oscillatory reconnection
in which the two flux ropes merge into a single flux rope. We find that
oscillatory reconnection can occur intrinsically without an external
oscillatory driver during flux rope coalescence, which may occur both during
large-scale coronal loop interactions and the merging of plasmoids in
fragmented current sheets. Furthermore, we demonstrate that radially
propagating non-linear waves are produced in the aftermath of flux rope
coalescence, due to the post-reconnection oscillations of the merged flux rope.
The behaviour of these waves is found to be almost independent of the initial
out-of-plane magnetic field. It is estimated that the waves emitted through
merging coronal loops and merging plasmoids in loop-top current sheets would
have a typical phase speed of 90 km/s and 900 km/s respectively. It is possible
that the properties of the waves emitted during flux rope coalescence could be
used as a diagnostic tool to determine physical parameters within a coalescing
region.
