  Scaling properties of a self-dual field-theoretical model, describing two
weakl$spinless Luttinger chains, are studied. A crossover to a sine-Gordon
massive phase, with strongly developed two-particleinterchain correlations, is
described. It is argued that, in a wide range of the in-chain interaction,
renormalization of the interchain hopping amplitude is determined by the
Luttinger liquid effects.
