We use the recently found matrix description of noncritical superstring
theory of Type 0A to compute tachyon scattering amplitudes in a background with
a RR flux. We find that after the string coupling is multiplicatively
renormalized, the amplitudes in any genus become polynomial in the RR flux. We
propose that in the limit where both the string coupling and the RR flux go to
infinity, the theory has a weakly-coupled description in terms of another
superstring theory with a vanishingly small RR flux. This duality exchanges the
inverse string coupling and the 0-brane charge. The dual superstring theory
must have a peculiar property that its only field-theoretic degree of freedom
is a massless RR scalar.Comment: 12 pages, late
