Instantons in the quark plasma. The two loop approximation

The thermodynamics of the quark plasma is studied by means of the exact Green functions in the instanton field. The correction to the instanton action due to the interaction with cold (T approaches 0) plasma of the light quarks is computed up to the g(2)-terms. The action falls abruptly when the instanton radius increases and the effects of instanton suppression by plasma are absent. Large instantons are strongly distorted by plasma and there are no instantons greater than the Debye radius.