  We continue our study of solitons in noncommutative gauge theories and
present an extremely simple BPS solution of N=4 U(1) noncommutative gauge
theory in 4 dimensions, which describes N infinite D1 strings that pierce a D3
brane at various points, in the presence of a background B-field in the
Seiberg-Witten limit. We call this solution the N-fluxon. For N=1 we calculate
the complete spectrum of small fluctuations about the fluxon and find three
kinds of modes: the fluctuations of the superstring in 10 dimensions arising
from fundamental strings attached to the D1strings, the ordinary particles of
the gauge theory in 4 dimensions and a set of states with discrete spectrum,
localized at the intersection point--- corresponding to fundamental strings
stretched between the D1string and the D3 brane. We discuss the fluctuations
about theN-fluxon as well and derive explicit expressions for the amplitudes of
interactions between these various modes. We show that translations in
noncommutative gauge theories are equivalent to gauge transformations (plus a
constant shift of the gauge field) and discuss the implications for the
translational zeromodes of our solitons. We also find the dyonic versions of
N-fluxon, as well as of our previous string-monopole solution.
