The ensemble of Euclidean gluon field configurations represented by the domain wall network is considered. A single domain wall is given by the sine-Gordon kink for the angle between chromomagnetic and chromoelectric components of the gauge field. The domain wall separates the regions with self-dual and anti-self-dual fields. The network of the domain wall defects is introduced as a combination of multiplicative and additive superpositions of kinks. The character of the spectrum and eigenmodes of color-charged fluctuations in the presence of the domain wall network is discussed. The concept of the confinement-deconfinement transition in terms of the ensemble of domain wall networks is outlined. Conditions for the formation of a stable thick domain wall junction (the chromomagnetic trap) during heavy ion collisions are discussed, and the spectrum of color charged quasiparticles inside the trap is evaluated. An important observation is the existence of the critical size Lc of the trap stable against gluon tachyonic modes, which means that deconfinement can occur only in a finite region of space-time in principle. The size Lc is related to the value of gluon condensate g 2 F 2 .

An approach to QCD vacuum as a medium describable in terms of statistical ensemble of almost everywhere homogeneous Abelian (anti-)self-dual gluon fields is briefly reviewed. These fields play the role of the confining medium for color charged fields as well as underline the mechanism of realization of chiral SUL(N f ) × SUR(N f ) and UA(1) symmetries. Hadronization formalism based on this ensemble leads to manifestly defined quantum effective meson action. Strong, electromagnetic and weak interactions of mesons are represented in the action in terms of nonlocal n-point interaction vertices given by the quark-gluon loops averaged over the background ensemble. New systematic results for the mass spectrum and decay constants of radially excited light, heavy-light mesons and heavy quarkonia are presented. Interrelation between the present approach, models based on ideas of soft wall AdS/QCD, light front holographic QCD, and the picture of harmonic confinement is outlined.

Transition form factors F P γ * γ ( * ) of pseudoscalar mesons are studied within the framework of the domain model of confinement, chiral symmetry breaking and hadronization. In this model, the QCD vacuum is described by the statistical ensemble of domain wall networks which represents the almost everywhere homogeneous Abelian (anti-)self-dual gluon field configurations. Calculations of the form factors are performed consistently with mass spectra of light, heavy-light and double-heavy mesons, their weak and strong decay constants. Influence of the nonperturbative intermediate range gluon fields on asymptotic behaviour of pion transition form factor is of particular interest, as it can potentially lead to the growth of Q 2 Fπγ * γ(Q 2 ). It is found that Q 2 Fπγ * γ(Q 2 ) approaches a constant value at asymptotically large Q 2 . However, this limit differs from the standard factorization bound, though for pion form factor complies with Belle data more likely than with BaBar ones. At the same time the generally accepted factorization bound is shown to be satisfied for the case of the symmetric kinematics,

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