  It is well known that major solar eruptions are often produced by active
regions with continual photospheric shearing and converging motions. Here,
through high accuracy magnetohydrodynamics simulation, we show how solar
eruption is initiated in a single bipolar configuration as driven by first
shearing and then converging motions at the bottom surface. Different from many
previous simulations, we applied the converging motion without magnetic
diffusion, thus it only increases the magnetic gradient across the polarity
inversion line but without magnetic flux cancellation. The converging motion at
the footpoints of the sheared arcade creates a current sheet in a quasi-static
way, and the eruption is triggered by magnetic reconnection of the current
sheet, which supports the same scenario as shown in our previous simulation
with only shearing motion. With the converging motion, the current sheet is
formed at a lower height and has a higher current density than with shearing
motion alone, which makes reconnection more effective and eruption stronger.
Moreover, the converging motion renders a fast decay rate of the overlying
field with height and thus favorable for an eruption. This demonstrate that the
converging flow is more efficient to create the current sheet and more
favorable for eruption than by solely the shearing flow.
