Patent Number: 
Section: claims

1. A pulsed generator of a pinch plasma comprising:two opposed coaxially aligned electrodes with convex profiles;a steady magnetic field applied parallel to the common axis of the electrodes;a limiter disc located between the electrodes with a hole centered on the axis, and a fill of low pressure gas, wherein:a pulsed voltage between the electrodes drives a current initially in a cylindrical sheet of diameter defined by the said hole, the current sheet being collapsed by the plasma pinch effect onto the convex surfaces of the electrodes, compressing the static magnetic field into a protective sheath over each surface, and forming a dense, high temperature plasma pinch on the axis between the electrodes. 2. A generator as in claim 1, driven by an alternating pulsed voltage. 3. A generator as in claim 1, in which the pulse frequency is sufficiently high for partial gas ionization to persist between pulses. 4. A generator as in claim 1, in which an ignition voltage pulse is applied to the limiter disc prior to the application of the main current pulse. 5. A generator as in claim 1, in which the convex electrode profiles are substantially conical. 6. An extreme ultraviolet source system comprising at a minimum the plasma pinch generator of claim 1, a collector reflective optical element, and means to reduce the working gas pressure along the path from the plasma to the point of use. 7. A generator as in claim 1, with a plurality of limiter discs distributed between the electrodes. 8. A generator as in claim 7, in which the working gas is a metal vapor contained by helium gas in a wide angle heat pipe, the limiter discs having conical shapes and comprising the metal vapor condensation and return surfaces of the heat pipe. 9. An extreme ultraviolet source based on the 13.5 nm emission of doubly-ionized lithium energized by a plasma pinch formed in the plasma generator of claim 8. 10. An extreme ultraviolet source based on the emission of a metal ion energized in the plasma pinch generator of claim 8 with the plasma further heated in a small volume by a pulsed laser to enhance EUV emission from the heated region. 11. An extreme ultraviolet source based on the 13.5 nm emission of doubly-ionized lithium energized in the plasma pinch generator of claim 8 with the plasma further heated in a small volume by a pulsed carbon dioxide laser to enhance 13.5 nm emission from the heated region. 12. A generator as in claim 8, in which metal vapor is charged and replenished by evaporation from a chamber internal to an electrode via a small hole on the axis of an electrode.