Trapped Plasmas with a Single Sign of Charge

Despite their reputation, not all plasmas are difficult to confine. In fact, one kind of plasma can be kept for long times in a simple apparatus by means of static electric and magnetic fields. It is the kind of plasma that consists exclusively of particles with a single sign of charge. Examples include pure electron plasmas, positive ion plasmas of one or more species, positron plasmas and even electron-antiproton plasmas—all of which have been realized in recent experiments.