Critical Loss Radius in a Penning Trap Subject to Multipole Fields
When particles in a Penning trap are subject to a magnetic multipole field, those beyond a critical radius will be lost. The critical radius depends on the history by which the field is applied, and can be much smaller if the particles are injected into a preexisting multipole than if the particles are subject to a ramped multipole. Both cases are relevant to ongoing experiments designed to trap antihydrogen.
J. Fajans, N. Madsen, and F. Robicheaux, Phys. Plasmas 15, 032108 (2008)