<i>z</i>-pinch plasma lens focusing of a heavy-ion beam

Abstract

For the first time a heavy-ion beam was focused using a z-pinch plasma lens. The diameter of an incident, parallel, 460-MeV argon-ion beam was reduced from \ensuremath{\sim}8 mm (FWHM) to \ensuremath{\sim}2 mm within 230 mm downstream of the plasma. Inside a cylindrically symmetric plasma column a high-gradient, azimuthal magnetic field is produced during a z-pinch discharge. For axially moving, high-energy charged particles this field configuration provides strong, first-order focusing simultaneously in both transversal planes. The measured spot size agrees with numerical calculations taking into account the finite beam emittance, and charge exchange as well as energy-loss processes contributing to aberrations.