Possible control scenario of radial electric field by loss cone particle injection into a helical device

The possibility of controlling the radial electric field of toroidal plasma s by injecting high energy electrons along the reversible loss cone orbit o f helical magnetic traps is investigated. It is well known that the radial electric field plays an important role in the confinement improvement scena rio, especially in the low collisional regime in the physics picture of neo classical theory. For this purpose, it is made clear that the most suitable particles are transit particles, which show a transition from helically tr apped orbits to blocked ones. It is also found that a parallel AC electric field launched from outside assists this transition and makes it possible f or particles to penetrate deeply into the plasma. In addition it is confirm ed that the viscosity of the plasma coupled with the helical field configur ation provides a bifurcation of plasma states and its stable solution resul ts in an improvement of confinement.