The invention relates to a plasma generator (1) for cleaning an object. The plasma generator (1) comprises a plasma chamber (2) and a support structure (6) arranged in the plasma chamber for supporting the object (7) to be cleaned. Further, the plasma generator comprises an electromagnetic shield (5a, 5b, 5c) counteracting a flow of charged plasma particles flowing from a plasma generating region towards the object, and a plasma source (8). In addition, the plasma generator comprises an additional plasma source (9,10) to form a composition of plasma sources that are arranged to generate in the plasma generating region plasmas, respectively, that mutually interact during operation of the plasma generator so as to force plasma particles to flow in a diffusely closed flow path.