Positron trapping in a magnetic mirror configuration

In a first step toward generating an electron–positron plasma, a proof-of-principle experiment is reported in which externally injected slow positrons are trapped in a magnetic mirror configuration by electron cyclotron resonance heating. With a primary flux of only 530 slow positrons/s from a 600 μCi Na-22 positron source/moderator system, an estimated equilibrium density of 5×102 cm−3 is obtained in a 20 cm3 volume. With an appropriate increase of the injected positron flux, densities in the 107 cm−3 range can be expected.