Virtual gap dielectric wall accelerator

#1. Field of the Invention

#This invention pertains generally to particle accelerators, and more particularly to dielectric wall accelerators.

#2. Description of Related Art

#The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only:

#FIGS. 1A-D illustrate the basic principles of the invention.

#FIGS. 2A-C are cross-sectional views of three embodiments of the virtual gap accelerator of the invention, along with simple circuit models thereof.

#Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus and method generally shown in FIG. 1A through FIG. 9. It will be appreciated that the apparatus may vary as to configuration and as to details of the parts, and the method may vary as to its particular implementation and as to specific steps and sequence, without departing from the basic concepts as disclosed herein.

#The invention is a dielectric wall accelerator (DWA) in which a virtual, moving accelerating gap is formed along an insulating tube by controlling the conductivity of the tube at sequential local regions thereof. Localized voltage concentration is achieved by sequential activation of high resistance along a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a “virtual” traveling gap along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region (the virtual gap) where the resistance is high. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

#FIG. 1A shows a conductive tube 10 made up of two segments 12, 14 separated by a narrow gap 16 around the tube. One end of tube 10, i.e. segment 12, is connected to a voltage source V, and the other end of tube 10, i.e. segment 14, is connected to ground. The voltage drop V along tube 10 will then occur almost entirely at the gap 16, because gap 16 represents a nonconductive or highly resistive region along the conductive or low resistivity tube 10. This voltage drop at the gap 16 will produce an electric field or lens 18 in the tube 10. Electric field 18 would accelerate a charged particle 30 that passes axially through tube 10.