Physicists have discovered a possible solution to a mystery that has long baffled researchers working to harness fusion. If confirmed by experiment, the finding could help scientists eliminate a major impediment to the development of fusion as a clean and abundant source of energy for producing electric power. Tiny bubble-like islands in hot charged gases (plasmas) , collect impurities that cool the plasma, the root of a long standing problem knows as the “density limit” that prevent fusion reactors to operate at maximum effciency. read : Scientists see solution to critical barrier to fusion.