USA As Represented by Secretary of the Navy

Other

Christos A Kapetanakos

Jeffry Golden

Redge A Mahaffey

Phillip A Sprangle

John A Pasour

Spencer J Marsh

A betatron for accelerating charged particles in a toroidal vacuum chamber comprising

Betatron accelerator having high ratio of Budker parameter to

A system based on the magnetic compression of ion rings, for generating intense (high-current), high-energy ion pulses that are guided to a target without a metallic wall or an applied external magnetic field includes a vacuum chamber; an inverse reflex tetrode for producing a hollow ion beam within the chamber; magnetic coils for producing a magnetic field, B.sub.o, along the axis of the chamber; a disc that sharpens a magnetic cusp for providing a rotational velocity to the beam and causing the beam to rotate; first and second gate coils for producing fast-rising magnetic field gates, the gates being spaced apart, each gate modifying a corresponding magnetic mirror peak (near and far peaks) for trapping or extracting the ions from the magnetic mirror, the ions forming a ring or layer having rotational energy; a metal liner for generating by magnetic flux compression a high, time-varying magnetic field, the time-varying magnetic field progressively increasing the kinetic energy of the ions, the magnetic field from the second gate coil decreasing the far mirror peak at the end of the compression for extracting the trapped rotating ions from the confining mirror; and a disc that sharpens a magnetic half-cusp for increasing the translational velocity of the ion beam. The system utilizes the self-magnetic field of the rotating, propagating ion beam to prevent the beam from expanding radially upon extraction.

Generation of intense, high-energy ion pulses by magnetic compression of

An inverse reflex tetrode (IRT) for producing an intense pulsed beam of i includes a real cathode having a curved or conical surface which is substantially transparent to the ions; first anode and second anode, or grid, which are spaced apart and are at the same potential, the first anode being between the real cathode and the second anode and having a curved or conical surface approximately parallel to the surface of the real cathode, and also being formed from a dielectric material such as polyethylene; a curved or conical hollow anode stalk which supports both anodes; and a virtual cathode which is formed by electrons that are emitted by the real cathode and pass through the first anode. The real cathode and first and second anodes are enclosed in a vacuum chamber and are immersed in an applied external magnetic field. The IRT receives an electrical pulse from a high-voltage pulse generator. The real cathode emits electrons which accelerate toward the first anode, pass through the first anode and form a virtual cathode between the first and second anodes. Most of the electrons oscillate between the virtual cathode and the real cathode and form a plasma sheath on the surfaces of the first anode. Some ions from the plasma propagate toward the second anode, and some ions propagate toward the real cathode. The ions arrive at the second anode with zero velocity, while the other ions pass through the real cathode and form a propagating ion beam.

Intense ion beam generation with an inverse reflex tetrode (IRT)

A reflex tetrode device for efficiently generating intense, pulsed unidirional ion beams. The device includes two thin, semitransparent anodes spaced from a real cathode which is maintained at ground potential. The first anode is spaced from and faces the real cathode. The second anode is spaced a short distance from the first anode and a virtual cathode is formed beyond the second anode when a sufficiently high electron current flows from the real cathode and through the anodes. The anodes are ring-like or disc-like structures secured to the edges of a support member with their planes perpendicular to the axis of the device between the real and virtual cathodes. The anode structure (i.e., the support member together with the two anodes) is connected to a pulsed high-voltage generator which is operated in positive polarity. Consequently, both anodes are at the same positive potential. The first anode, because of its material, does not readily form an ionic plasma when electrons pass through it, but the second anode does.

Reflex tetrode for producing an efficient unidirectional ion beam

A reflecting electron tube for producing high-power, high-frequency, monoomatic microwave pulses includes an anode which produces little or no ion flux when struck by electrons emitted from a cathode, and requires no applied, external magnetic field. An anode support holding the anode and a cathode shank which supports the cathode are positioned within a vacuum chamber such that the anode is closely spaced from the cathode. The anode support is connected to a pulsed high-voltage supply located external to the chamber. The anode is formed from a material which does not produce a significant amount of ion flux but does permit electrons emitted from the cathode to oscillate through the anode. Electrons oscillating in phase bunch together within the potential well of the system and emit microwave radiation.

High-power microwaves from a non-isochronous reflecting electron system

A reflex triode for use in producing ultra-high-current (&gt;10.sup.5 A), ul-high-power (&gt;10.sup.11 W) ion beams includes an improved anode and an improved cathode and has a low inductance design. A cylindrical anode stalk supporting the anode is positioned inside of and closely spaced from a cylindrical cathode shank which supports the cathode. Magnetic insulation allows for a close spacing between the anode stalk and cathode shank which reduces the inductance. The improved cathode is embedded in a cathode mount to reduce divergence of the ion beam. The improved anode consists of conducting concentric rings with thin film in the space between the rings to produce a more uniformly dense ion beam having low divergence.

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Bethesda, MD, United States of America

Christos A Kapetanakos