The possibility of controlling the radial electric field of toroidalplasmas by injecting high energy electrons along the reversible losscone orbit of helical magnetic traps is investigated. It is wellknown that the radial electric field plays an important role in theconfinement improvement scenario, especially in the low collisionalregime in the physics picture of neoclassical theory. For thispurpose, it is made clear that the most suitable particles are transitparticles, which show a transition from helically trapped orbitsto blocked ones. It is also found that a parallel AC electric fieldlaunched from outside assists this transition and makes it possiblefor particles to penetrate deeply into the plasma. In addition it is confirmedthat the viscosity of the plasma coupled with the helicalfield configuration provides a bifurcation of plasma states and itsstable solution results in an improvement of confinement.
Overview of results from the Large Helical Device