Simple Mechanism of Softening Structure Functions at Low Transverse   Momentum Region
  The relevance of the dipole configurations of quarks in forming nucleus structure functions is discussed. It is shown that a radiation generated by dipole configurations while moving relativistically along their axises is described by distributions which are finite and infrared stable in low transverse momentum region. It is argued that there is an exponential transition to the perturbative regime of large transverse momenta and its power is defined by the distance between the dipole charges in its rest frame $m^{-1}_\pi$. 
S.V.Molodtsov, A.M.Snigirev, G.M.Zinovjev