Time Evolution via S-branes

Using S(pacelike)-branes defined through rolling tachyon solutions, we show how the dynamical formation of D(irichlet)-branes and strings in tachyon condensation can be understood. Specifically we present solutions of S-brane actions illustrating the classical confinement of electric and magnetic flux into fundamental strings and D-branes. The role of S-branes in string theory is further clarified and their RR charges are discussed. In addition, by examining ``boosted'' S-branes, we find what appears to be a surprising dual S-brane description of strings and D-branes, which also indicates that the critical electric field can be considered as a self-dual point in string theory. We also introduce new tachyonic S-branes as Euclidean counterparts to non-BPS branes.