Plasma lens fine focusing of heavy-ion beams

The fine-focusing capability of a current-carrying, "active" plasma lens has been demonstracted for the first time. A cylindrically symmetric argon discharge plasma pulsed with an oscillating current of over 20 kA in amplitude served as a current conducting medium. With this plasma lens has been demonstrated for the first time. A cylindrically symmetric argon discharge plasma pulsed with an oscillating current of over 20 kA in amplitude served as a current conducting medium. With this plasma lens the diameter of an incident 2.2-GeV gold ion beam from the linear accelerator UNILAC at GSI-Darmstadt was focused from initially 10 to about 0.25 mm, at a focal length of only 140 mm. The gradient of the azimuthal magnetic field exceeded 120 T/m. The striking features of this first-order and strong-focusing plasma lens favor its use as a precise high-gradient focusing device for high-energy charged particles.