Geometry of the Nonabelian DBI Dyonic Instanton

We introduce a calculus of the Lie algebra valued functions present in Tseytlin’s proposal for the nonabelian DBI action, and apply it to show that the recently found dyonic instanton is a solution of the full nonabelian DBI action. The geometry of this solution exhibits a new effect of blowing-up'' of the brane, which was not present in the case of the brane realisation of monopoles. We interpret this solution as the superposition of the D0 brane and fundamental string F1 which connects two separated D4 branes. Both F1 and D0 are delocalised in the blown-up’’ region between two separated D4 branes.