It has been shown that hybrid inflation may end with the formation of
non-topological solitons of inflaton field. As a first step towards a fully
realistic picture of the post-inflation era and reheating in supersymmetric
hybrid inflation models, we study the classical scalar field equations of a
supersymmetric hybrid inflation model using a semi-analytical ansatz for the
spatial dependence of the fields. Using the minimal D-term inflation model as
an example, the inflaton field is evolved using the full 1-loop effective
potential from the slow-rolling era to the U(1)_{FI} symmetry-breaking phase
transition. Spatial perturbations of the inflaton corresponding to quantum
fluctuations are introduced for the case where there is spatially coherent
U(1)_{FI} symmetry breaking. The maximal growth of the dominant perturbation is
found to depend only on the ratio of superpotential coupling \lambda to the
gauge coupling g. The inflaton condensate fragments to non-topological solitons
for \lambda/g > 0.09. Possible consequences of non-topological soliton
formation in fully realistic SUSY hybrid inflation models are discussed.Comment: 27 pages LaTeX, 8 figures. Additional references and discussio