This info ( viewtopic.php?t=2401 ), touching on the use of bulk, high-temp superconductors, led me to think about using bulk HTS for constraining the paths of p-B11 fusion alpha particles via diamagnetic exclusion of the magnetic self-field. Probably won't work because the energies (velocities) are so high, but just in case...
Maybe someone who has internet access to these can see if energetic helium ions are mentioned anywhere:
Focusing characteristics of a modified double-layered high-Tc superconducting tube (supertron) for charged particle beams Sep 2001
Supertrons: high-Tc superconducting tube lenses for electron beams — a double-layered tube Jun 2000
Focusing and guiding charged particles by a superconducting tube May 1995
Focusing a charged-particle beam by a superconductor Sep 1994
High Tc bulk superconductor wigglers Sep 1991
Profiles of Relativistic Electron Beams Focused with High-Temperature Superconducting Lenses (Supertrons) Apr 1990