Dbrane Near NS5-branes: with Electromagnetic Field

We study the Dp-brane dynamics near NS5-branes with constant electromagnetic field. In the framework of effective Dirac-Born-Infeld action, we investigate the effect of the electromagnetic field on the Dp-brane dynamics. The radial motion of the Dp-brane on the transverse directions of NS5-branes can be mapped to a rolling tachyon in a constant NS Bμν background. In the near throat region, the classical motion can be identified with the rescaled hairpin. After constructing the boundary state of the rescaled hairpin, we discuss the closed string emission of the Dp-brane and find that the energy of the closed string emission is always finite in the presence of constant electric field. Taking the winding strings into account, the emitted energy is divergent, indicating that the emitted winding strings carry away most of the energy. ∗e-mail address:[email protected] †e-mail address: [email protected] ‡e-mail address: [email protected]