  We study the emergence of a toroidal flux tube into the solar atmosphere and
its interaction with a pre-existing field of an active region. We investigate
the emission of jets as a result of repeated reconnection events between
colliding magnetic fields. We perform 3D simulations by solving the
time-dependent, resistive MHD equations in a highly stratified atmosphere. A
small active region field is constructed by the emergence of a toroidal
magnetic flux tube. A current structure is build up and reconnection sets in
when new emerging flux comes into contact with the ambient field of the active
region. The topology of the magnetic field around the current structure is
drastically modified during reconnection. The modification results in a
formation of new magnetic systems that eventually collide and reconnect. We
find that reconnection jets are taking place in successive recurrent phases in
directions perpendicular to each other, while in each phase they release
magnetic energy and hot plasma into the solar atmosphere. After a series of
recurrent appearance of jets, the system approaches an equilibrium where the
efficiency of the reconnection is substantially reduced. We deduce that the
emergence of new magnetic flux introduces a perturbation to the active region
field, which in turn causes reconnection between neighboring magnetic fields
and the release of the trapped energy in the form of jet-like emissions. This
is the first time that self-consistent recurrency of jets in active regions is
shown in a three-dimensional experiment of magnetic flux emergence.
