Simple mechanism of softening structure functions at low transverse momenta

The relevance of the dipole configurations of quarks in forming nuclear str ucture functions is discussed. It is shown that a radiation generated by di pole configurations moving relativistically along their axes is described b y distributions that are finite and infrared-stable in the low-transverse-m omentum region. It is argued that there is an exponential transition to the perturbative regime of large transverse momenta and that its power is defi ned by the distance between the charges of the dipole in its rest frame (m( pi)(-1)).