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We study the dependence of quark condensate $\Sigma$ on an external magnetic field. For weak fields, it rises linearly with the field. Pion mass and residue are also shifted so that the Gell-Mann - Oakes - Renner relation is satisfied. In the strong field region, $\Sigma(H) \propto (eH)^{3/2}$.Comment: 13 pages LaTeX, 5 postscript files for figure

We show that, in 1+1 dimensional gauge theories, a heavy probe charge is screened by dynamical massless fermions both in the case when the source and the dynamical fermions belong to the same representation of the gauge group and, unexpectedly, in the case when the representation of the probe charge is smaller than the representation of the massless fermions . Thus, a fractionally charged heavy probe is screened by dynamical fermions of integer charge in the massless Schwinger model, and a colored probe in the fundamental representation is screened in QCD 2 with adjoint massless Majorana fermions. The screening disappears and confinement is restored as soon as the dynamical fermions are given a nonzero mass. For small masses, the string tension is given by the product of the light fermion mass and the fermion condensate with a known numerical coefficient. Parallels with 3+1 dimensional QCD and supersymmetric gauge theories are discussed.