Patent Number: 
Section: claims

1. A non-resonance photo-neutralizer for neutral beam injectors comprisingfirst and second mirrors having opposing mirror surfaces, the first and second mirrors being positioned in spaced relation and extending longitudinally in a first direction, the first mirror having a central portion and opposing first and second ends spaced apart from the central portion in the first direction, the first mirror extending in the first direction from the first end to the central portion and along the central portion in the first direction to the second end, and the first mirror bending along the first direction toward the second mirror with the first and second ends of the first mirror being positioned closer to the second mirror than the central portion of the first mirror,wherein the mirror surface of the first mirror is concave in a second direction transverse to the first direction. 2. The photo-neutralizer of claim 1 wherein the first and second mirrors forming a photon trap in a space there between, wherein the photon trap having a spherical, elliptical, cylindrical or toroidal shape defined by the first and second mirrors. 3. The photo-neutralizer of claim 1 wherein a space interposing the first and second mirrors forming a photon trap, wherein the photon trap comprises a confinement region adjacent a family of normals common to the mirror surfaces of the first and second mirrors. 4. The photo-neutralizer of claim 1 wherein one or more of the mirror surfaces of the first and second mirrors are concave. 5. The photo-neutralizer of claim 1 wherein the mirror surface of the first mirror is concave and the mirror surface of the second mirror is flat. 6. The photo-neutralizer of claim 5 wherein the first mirror comprises a mirror assembly including a central mirror and first and second outer mirrors coupled to the central mirror. 7. The photo-neutralizer of claim 6 wherein the central mirror is cylindrically shaped and the outer mirrors are conically shaped. 8. A negative ion based neutral beam injector comprisinga negative ion source, anda non-resonance photo-neutralizer co-axially positioned with the negative ion source, wherein the photo-neutralizer including first and second mirrors having opposing mirror surfaces, the first and second mirrors being positioned in spaced relation and extending longitudinally in a first direction, the first mirror having a central portion and opposing first and second ends spaced apart from the central portion in the first direction, the first mirror extending in the first direction from the first end to the central portion and along the central portion in the first direction to the second end, and the first mirror bending along the first direction toward the second mirror with the first and second ends of the first mirror being positioned closer to the second mirror than the central portion of the first mirror, wherein the mirror surface of the first mirror is concave in a second direction transverse to the first direction. 9. The neutral beam injector of claim 8 wherein the first and second mirrors forming a photon trap in a space there between, wherein the photon trap having a spherical, elliptical, cylindrical or toroidal shape defined by the first and second mirrors. 10. The neutral beam injector of claim 8 wherein a space interposing the first and second mirrors forming a photon trap, wherein the photon trap comprises a confinement region adjacent a family of normals common to the first and second mirror surfaces. 11. The neutral beam injector of claim 8 wherein one or more of the mirror surfaces of the first and second mirrors are concave. 12. The neutral beam injector of claim 8 wherein the mirror surface of the first mirror is concave and the mirror surface of the second mirror is flat. 13. The neutral beam injector of claim 12 wherein the first mirror comprises a mirror assembly including a central mirror and first and second outer mirrors coupled to the central mirror. 14. The neutral beam injector of claim 13 wherein the central mirror is cylindrically shaped and the outer mirrors are conically shaped.