  Large-scale solar eruptions are believed to have a magnetic flux rope as the
core structure. However, it remains elusive as to how the flux rope builds up
and what triggers its eruption. Recent observations found that a prominence
erupted following multiple episodes of "flux feeding". During each episode, a
chromospheric fibril rose and merged with the prominence lying above. In this
letter, we carried out 2.5-dimensional magnetohydrodynamic (MHD) numerical
simulations to investigate whether the flux-feeding mechanism can explain such
an eruption. The simulations demonstrate that the discrete emergence of small
flux ropes can initiate eruptions by feeding axial flux into the preexistent
flux rope until its total axial flux reaches a critical value. The onset of the
eruption is dominated by an ideal MHD process. Our simulation results
corroborate that the flux feeding is a viable mechanism to cause the eruption
of solar magnetic flux ropes.
