The NRL ion ring program

An experiment is underway to form a strong proton ring using the 200 kA, 1.2 MeV, 50 nsec hollow proton beam recently generated at NRL. The 5 m long magnetic field configuration consists of a magnetic cusp, a compressing magnetic field, a gate field and a magnetic mirror. The midplane value of the magnetic mirror is such that the major radius of the ring will be about 10 cm. The degree of field reversal that will be achieved with the 5 × 10¹⁶ protons per pulse from the existing beam depends upon the field reversal is possible with the 600 kA proton beam that would be generated from the low inductance coaxial triode coupled to the upgraded Gamble II generator. The propagation and trapping of an intense proton beam in the expermental magnetic field configuration is investigated numerically. The results show that the self magnetic field has a very pronounced effect on the dynamics of the gyrating protons.