Abstract: An apparatus for cutting annular corrugations in an interior surface of a cylindrical tube having a cutter head comprising a plurality of cutting teeth; a drive shaft coupled to the cutter head for spinning the cutter head; a mandrel coupled to the cutter head, wherein the mandrel defines a longitudinal axis, wherein an axis of rotation of the cutter head is parallel to, but in a position not coaxial with the axis of rotation of the cutter head; an outer eccentric coupled to mandrel, wherein the outer eccentric rotates the mandrel, wherein the axis of rotation orbits around the longitudinal axis.

Abstract: An apparatus for cutting annular corrugations in an interior surface of a cylindrical tube having a cutter head comprising a plurality of cutting teeth; a drive shaft coupled to the cutter head for spinning the cutter head; a mandrel coupled to the cutter head, wherein the mandrel defines a longitudinal axis, wherein an axis of rotation of the cutter head is parallel to, but in a position not coaxial with the axis of rotation of the cutter head; an outer eccentric coupled to mandrel, wherein the outer eccentric rotates the mandrel, wherein the axis of rotation orbits around the longitudinal axis.

Abstract: An apparatus for cutting annular corrugations in an interior surface of a cylindrical tube having a cutter head comprising a plurality of cutting teeth; a drive shaft coupled to the cutter head for spinning the cutter head; a mandrel coupled to the cutter head, wherein the mandrel defines a longitudinal axis, wherein an axis of rotation of the cutter head is parallel to, but in a position not coaxial with the axis of rotation of the cutter head; an outer eccentric coupled to mandrel, wherein the outer eccentric rotates the mandrel, wherein the axis of rotation orbits around the longitudinal axis.

Abstract: An apparatus for cutting annular corrugations in an interior surface of a cylindrical tube having a cutter head comprising a plurality of cutting teeth; a drive shaft coupled to the cutter head for spinning the cutter head; a mandrel coupled to the cutter head, wherein the mandrel defines a longitudinal axis, wherein an axis of rotation of the cutter head is parallel to, but in a position not coaxial with the axis of rotation of the cutter head; an outer eccentric coupled to mandrel, wherein the outer eccentric rotates the mandrel, wherein the axis of rotation orbits around the longitudinal axis.

Abstract: The present embodiments providing methods, systems and apparatuses of protecting a surface during laser machining. In some embodiments, a method of protecting a surface during laser machining comprises: directing a fluid into a cavity of an object being laser machined, where the fluid does not have laser absorption properties; and directing a plurality of laser pulses at a wall of the object being laser machined, where the laser pulses are configured to form a hole through the wall such that at least one laser pulse passes through the hole and enters the cavity while the fluid is directed into the cavity such that the laser pulse is incident on the fluid and a surface together in order to inhibit backwall damage.

Abstract: An apparatus for producing a stable, high pressure plasma column with long length, and high axial uniformity. Rotating a gas-filled tube about an horizontal axis creates a vortex with minimal, or no shear flow. Such a vortex provides a stable equilibrium for a central column of high temperature gas and plasma when, for a given rotation speed, the centrifugal force dominates over the gravitational force inside the smallest radial dimension of the containment envelope. For gas pressures sufficiently high that the particle mean free path is short compared with the thickness of the gas layer between the central plasma column and the wall, thermal transport across this sheath layer is small and its temperature is low. High pressure discharges inside a rotating envelope may be sustained by a variety of means, including electrical, electromagnetic and chemical; they may find application in plasma torches, light sources, etc.

Abstract: An apparatus for producing a stable, high pressure plasma column with long length, and high axial uniformity. Rotating a gas-filled tube about an horizontal axis creates a vortex with minimal, or no shear flow. Such a vortex provides a stable equilibrium for a central column of high temperature gas and plasma when, for a given rotation speed, the centrifugal force dominates over the gravitational force inside the smallest radial dimension of the containment envelope. For gas pressures sufficiently high that the particle mean free path is short compared with the thickness of the gas layer between the central plasma column and the wall, thermal transport across this sheath layer is small and its temperature is low. High pressure discharges inside a rotating envelope may be sustained by a variety of means, including electrical, electromagnetic and chemical; they may find application in plasma torches, light sources, etc.

Abstract: An apparatus for producing a stable, high pressure plasma column with long length, and high axial uniformity. Rotating a gas-filled tube about an horizontal axis creates a vortex with minimal, or no shear flow. Such a vortex provides a stable equilibrium for a central column of high temperature gas and plasma when, for a given rotation speed, the centrifugal force dominates over the gravitational force inside the smallest radial dimension of the containment envelope. High pressure discharges inside a rotating envelope may be sustained by a variety of energy sources, including electrical, electromagnetic and chemical; they may find application in plasma torches, light sources, etc.

Abstract: A distributed microwave window couples microwave power in the HE.sub.11 mode between a first large diameter waveguide and a second large diameter waveguide, while providing a physical barrier between the two waveguides, without the need for any transitions to other shapes or diameters. The window comprises a stack of alternating dielectric and hollow metallic strips, brazed together to form a vacuum barrier. The vacuum barrier is either transverse to or tilted with respect to the waveguide axis. The strips are oriented to be perpendicular to the transverse electric field of the incident microwave power. A suitable coolant flows through the metallic strips. The metallic strips are tapered on both sides of the vacuum barrier, which taper serves to funnel the incident microwave power through the dielectric strips. The surfaces of the dielectric strips fronting the microwave power may be corrugated in a specified manner to reduce losses.

Abstract: A distributed microwave window couples microwave power in the HE.sub.11 mode between a first large diameter waveguide and a second large diameter waveguide, while providing a physical barrier between the two waveguides, without the need for any transitions to other shapes or diameters. The window comprises a stack of alternating dielectric and hollow metallic strips, brazed together to form a vacuum barrier. The vacuum barrier is either transverse to or tilted with respect to the waveguide axis. The strips are oriented to be perpendicular to the transverse electric field of the incident microwave power. A suitable coolant flows through the metallic strips. The metallic strips are tapered on both sides of the vacuum barrier, which taper serves to funnel the incident microwave power through the dielectric strips.

Abstract: A comb-line antenna structure (80) includes a multiplicity of parallel current straps (86) through which an appropriate rf electrical current passes in order to launch a desired magnetosonic wave (42) into an adjacent plasma mass (39). The current straps are mounted within a conductive, shallow, open box (88, 90) that faces the plasma mass. The current straps are inductively coupled, thereby requiring only a single rf input port (82) at one end of the comb-line structure. The rf input port provides a substantially constant impedance to an rf power source. A single rf output port (84) at the other end of the comb-line structure allows for the recirculation of the rf power. A multiplicity of U-shaped wickets (92) loop over and enclose each current strap. Such wickets function as a Faraday shield to shield the plasma and adjacent current straps from electrostatic fields.

Abstract: A unisex coupler assembly is disclosed capable of providing a leak tight coupling for waveguides with axial alignment of the waveguides and rotational capability. The sealing means of the coupler assembly are not exposed to RF energy, and the coupler assembly does not require the provision of external flanges on the waveguides. In a preferred embodiment, O ring seals are not used and the coupler assembly is, therefore, bakeable at a temperature up to about 150.degree. C. The coupler assembly comprises a split collar which clamps around the waveguides and a second collar which fastens to the split collar. The split collar contains an inner annular groove. Each of the waveguides is provided with an external annular groove which receives a retaining ring. The split collar is clamped around one of the waveguides with the inner annular groove of the split collar engaging the retaining ring carried in the external annular groove in the waveguide.

Abstract: Apparatus for generating high power microwaves and for radiating the microwave power in the HE.sub.1,1 mode into a confined plasma is disclosed. The apparatus includes a microwave generator and mode converters to convert the generated microwave power into the rectangular HE.sub.1,1 mode. A hermetically sealed rectangular HE.sub.1,1 mode power coupler is used between the plasma and a main waveguide run to seal the main waveguide run and the generator from the plasma. The power coupler comprises an input rectangular HE.sub.1,1 mode waveguide, an output rectangular HE.sub.1,1 mode waveguide and a plurality of dielectric sealed apertures through a common wall between the input and output waveguides. Power absorbed by the power coupler is removed by cooling fluid which is circulated through the common wall between the apertures.

Abstract: Conversion from a whispering gallery or volume mode to a more useable mode, such as the HE.sub.1,1 mode is achieved in a waveguide mode converter that includes input and output sections. The input section includes overlapping circular and coaxial waveguides. Microwave energy in a whispering gallery or volume mode within the circular waveguide is coupled through an array of N equally spaced axial slots placed in the common wall separating the circular waveguide and the coaxial waveguide to coaxial TE and TM modes. Helical grooves placed in one of walls of the coaxial waveguide convert the coaxial mode to a quasi parallel plate mode wherein the common wall separating the inner circular waveguide from the outer coaxial waveguide functions as one plate, and the outer wall of the coaxial waveguide functions as the other plate. The quasi parallel plate mode propagates microwave energy spirally through the coaxial waveguide in a direction k, where k makes an angle .theta. to the waveguide axis.

Abstract: A waveguide mode converter converts electromagnetic power being transmitted in a TE.sub.0n or a TM.sub.0n mode, where n is an integer, to an HE.sub.11 mode. The conversion process occurs in a single stage without requiring the power to pass through any intermediate modes. The converter comprises a length of circular corrugated waveguide formed in a multiperiod periodic curve. The period of the curve is selected to couple the desired modes and decouple undesired modes. The corrugation depth is selected to control the phase propagation constant, or wavenumbers, of the input and output modes, thereby preventing coherent coupling to competing modes. In one embodiment, both the period and amplitude of the curve may be selectively adjusted, thereby allowing the converter to be tuned to maximize the conversion efficiency.

Abstract: A corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations, provides birefringence for rotation of polarization in the HE.sub.11 mode. The corrugated waveguide may be fabricated by cutting circular grooves on a lathe in a cylindrical tube or rod of aluminum of a diameter suitable for the bore of the waveguide, and then cutting an approximation to ellipses for the corrugations using a cutting radius R.sub.0 from the bore axis that is greater than the bore radius, and then making two circular cuts using a radius R.sub.1 less than R.sub.0 at centers +b and -b from the axis of the waveguide bore. Alternatively, stock for the mandrel may be formed with an elliptical transverse cross section, and then only the circular grooves need be cut on a lathe, leaving elliptical corrugations between the grooves. In either case, the mandrel is first electroplated and then dissolved leaving a corrugated waveguide with noncircularly symmetric corrugations.

Abstract: A waveguide power divider (10) for splitting electromagnetic microwave power and directionally coupling the divided power includes an input waveguide (21) and reduced height output waveguides (23) interconnected by axial slots (22) and matched loads (25) and (26) positioned at the unused ends of input and output guides (21) and (23) respectively. The axial slots are of a length such that the wave in the input waveguide (21) is directionally coupled to the output waveguides (23). The widths of input guide (21) and output guides (23) are equal and the width of axial slots (22) is one half of the width of the input guide (21).

Abstract: Cyclotron breakdown is prevented in a partially evacuated waveguide by providing a section of waveguide having an axial cut therein in order to apply a potential across the two halves of the waveguide. This section is positioned in the waveguide crossing the area of electron cyclotron resonance. The potential applied across the waveguide halves is used to deflect seed electrons into the wall of the waveguide in order to prevent ionization of gas molecules and creation of more electron ion pairs which would result in cyclotron breakdown. Support means is also disclosed for electrically isolating the waveguide halves and transition means is provided between the section of the waveguide with the axial cut and the solid waveguide at either end thereof.

Abstract: A cyclotron resonance maser system includes coaxial coupling between coaxial wave guides. Such coupling is provided between an outer coaxial waveguide through which a gyrotron electron beam passes in generating or amplifying microwaves and an inner coaxial waveguide terminating in an annular window. The coupling separates the microwaves from the electron beam before the collector region of the gyrotron so that the collector dimensions are not related to, and hence restricted by, the wavelength of the output microwaves. The particular preferred coupling includes substantially axial slots in the common wall between the respective waveguides which slots provide selective coupling between the waveguides in the desired modes and limiting mode conversion. The coupling is preferably between a TE.sub.On or TE.sub.ml mode in the outer input waveguide and a TE.sub.On' mode in the inner, output waveguide, n and n' being integers greater than 1. A preferred resonant cavity limits the generated microwaves to a TE.sub.

Abstract: A cyclotron resonance maser microwave amplifier includes coaxial input and output waveguides. Coupling apparatus for cyclotron resonance maser microwave amplifiers and other microwave power systems is provided for transferring microwave power between first and second waveguides. Geometry permits unwanted modes to be effectively attenuated. The coupling apparatus includes first and second coaxial hollow metallic circularly cylindrical members. The first member forms a first waveguide section. A second waveguide section coaxial therewith is bounded internally by the first member, and externally by the second member. The first member has a plurality of apertures for transferring microwave power between the first and second waveguide sections. The apertures are small relative to the radius of the first member and are spaced around the circumference of the first member in a generally symmetrical array.