  The dynamical behavior of a fluxon in a semi-annular long Josephson junction
in the presence of an ac-drive is studied. The non-uniformity due to the non
uniform distribution of bias current is investigated. The oscillating potential
is found to increase the depinning current. Finite difference method is used
for numerical analysis and the response of the system to the ac-bias is
studied. The creation and annihilation of fluxon is also demonstrated
numerically for the first, second and third Zero-Field step cases.
