Abstract
A new scheme is proposed for synthesizing antihydrogen by trapping positrons at the centre of a field consisting of a magnetic quadrupole and an electric octupole. It is expected that the total electric field of this octupole with the space charge of the trapped positrons themselves will be strong enough to confine antiprotons inside the positron cloud, where the two particle species will combine to produce antihydrogen atoms spontaneously via radiative recombination. Furthermore, a numerical simulation has revealed that a considerable fraction of antihydrogen atoms in low-field-seeking states formed at 5 K near the centre of the trap may be transported as a 99% polarised beam and focused 1 m from the trap centre with ∼ 0.3% efficiency, corresponding to an enhancement in beam intensity by a factor 30.