A note on D-brane interactions in the IIA plane-wave background

We compute the D-brane tensions in the type IIA plane-wave background by comparing the interaction potential between widely separated D-branes in string theory with the supergravity mode exchange between the D-branes. We found that the D-brane tensions and RR charges in the plane-wave background are the same as those in the flat space. Also we work out the stringy halo behavior [C. Johnson, JHEP 0305 (2003) 055, hep-th/0303255] of the DpDp¯ spacelike branes and find the explicit dependence on the light cone separation r+. This suggests that the detailed tachyon dynamics for the spacelike DpDp¯ branes are different from those in the flat space case. We also discuss specific features of the exchange amplitudes in relation to the geometric properties of the IIA plane wave background. When branes are located at focal points, full or partial restoration of the translation invariance occurs and the amplitudes are similar to those in the flat space.