Localized energy concentration

Abstract

A system for generating a localized concentration of energy from an input shock wave (12) is provided. The system includes an amplifier (2) arranged to manipulate one or more of the velocity, pressure, or shape of the input shock wave (12). The amplifier (2) includes a body (33) made of a first material. The body (33) defines a cavity (35) for manipulating the input shock wave (12) to generate a manipulated shock wave. The cavity (35) includes an input portion (39) that receives the input shock wave (12) incident on the amplifier (2) and an output portion (311) that outputs the manipulated shock wave. The system further includes a target (4) configured to contain fuel, and the amplifier (2) and target (4) are arranged such that the manipulated shock wave is output from the amplifier (2) and incident on the target (4).

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for producing a high localized concentration of energy. [Background technology]

[0002] In Patent Document 1, it was shown that the interaction between shock waves of a non-gaseous medium and a gaseous medium can generate a high-velocity transverse jet of the non-gaseous medium moving through the gaseous medium, for example, causing the jet to impinge on and capture a volume of the gaseous medium against a target, which creates a strong concentration of energy within the gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2011 / 138622 Summary of the Invention

[0004] The present invention aims to provide an alternative technique for generating localized energy concentrations.

[0005] Viewed from a first aspect, the present invention provides a system for generating a localized concentration of energy, the system comprising: an amplifier arranged to manipulate one or more of the velocity, pressure or shape of the input shock wave, the amplifier comprising: a body comprising a first material; the body defining a cavity for manipulating the input shock wave to generate a manipulated shock wave; The cavity is an input section that receives the input shock wave incident on the amplifier; an output unit that outputs an operation shock wave; Equipped with The system further comprises a target configured to contain a fuel; The amplifier and the target are configured to be positioned such that the manipulation shock wave is output from the amplifier and impinges on the target.

[0006] Accordingly, the present invention provides a system comprising an amplifier for steering shock waves as they enter the amplifier, and a target for containing fuel such that the fuel is impacted by the steering shock waves output from the amplifier. The amplifier has an input (e.g., an opening) for receiving the input shock wave and an output (e.g., an opening) for outputting the steering shock wave. The cavity is designed (e.g., shaped) to steering the shock wave as it passes through the cavity.

[0007] Thus, it can be seen that by providing a system with an amplifier configured to manipulate the input shock wave independently of the target, the shock wave can be manipulated to impart higher pressures to the target. Additionally, the modular nature of the system (e.g., separate amplifiers and targets) allows different target designs to be used with different amplifier designs. This increases the configurability of the system, which can be particularly useful during experimentation.

[0008] The amplifier body, made of a first material, defines a cavity within the body, and thus the cavity, e.g., the volume defined by the body within the body, is preferably surrounded by the body (e.g., other than the input and output portions).

[0009] In an embodiment, the cavity contains a second material having a lower shock impedance than the first material. Preferably, the second material is between the input and output of the cavity. Thus, the body preferably comprises a material having a higher shock impedance than the (second) material of (e.g., at least a part of) the cavity or contained therein.

[0010] In embodiments, the amplifier (and thus the cavity) is formed such that the input section has a larger cross-sectional area than the (e.g., corresponding) cross-sectional area of the output section. The cross-sectional areas of the input and / or output sections may be defined in a plane that is substantially perpendicular to a predetermined direction between the input and output sections, e.g., such that the cross-sectional area of the input section is substantially parallel to the cross-sectional area of the output section, e.g., such that (the plane of) the input aperture is substantially parallel to (the plane of) the output aperture. The direction between the input and output sections may, in embodiments of the invention, be substantially parallel to a direction in which an input shock wave is arranged to propagate and enter the amplifier.

[0011] In embodiments, the amplifier (and thus the cavity) may be formed such that the cross-sectional area of the cavity in a plane generally perpendicular to the direction between the input and output may decrease linearly or non-linearly. In embodiments, the cross-sectional area of the cavity may initially increase and then decrease when moving from the input to the output. In embodiments, the cross-sectional area of the output may be larger than the cross-sectional area of the input (e.g., the cavity may have a flared output). Thus, for example, the cross-sectional area of the cavity may initially decrease and then increase when moving from the input to the output.

[0012] In an embodiment, the minimum distance between the input and output portions (e.g., the minimum distance between two points at the input and output portions (respective openings)) is greater than the maximum dimension of the output portion (e.g., the maximum distance from one point on the periphery to another point on the periphery, e.g., the diameter).

[0013] In an embodiment, the minimum distance between the input and output portions (e.g., the minimum distance between two points at the input and output portions (respective openings)) is greater than the maximum dimension of the input portion (e.g., the maximum distance from one point on the periphery to another point on the periphery, e.g., the diameter).

[0014] The body may have any suitable and desired dimensions, for example, as determined by the particular application of the amplifier. In one embodiment, the body (e.g., its cavity) has a thickness, diameter, and / or maximum dimension of between 0.1 mm and 100 mm, e.g., between 1 mm and 50 mm, e.g., between 2 mm and 10 mm, e.g., about 3 mm, 5 mm, or 8 mm.

[0015] In embodiments, the body is composed of (comprises, e.g., consists of) a first material, and the cavity contains (e.g., is at least partially filled with) a second material. In such embodiments, the second material has a lower shock impedance than the shock impedance of the first material. Thus, (the shape of) the cavity is defined by (e.g., its inner wall) the body (composed of) the first material, and the second material is located within the volume of the cavity.

[0016] It should be appreciated, therefore, that in embodiments, the amplifier can be used to manipulate (e.g., modify the shape and / or intensity of) the input shock wave due to the cavity (e.g., its shape) and the difference in shock impedance of the first and second materials. In this manner, the shock wave transmitted from the output of the cavity may have a greater intensity (e.g., energy) than the input shock wave received at the input of the cavity.

[0017] The body may have any suitable and desired shape (e.g., an (internal) wall having that shape) that defines the cavity. Preferably, the body has a dimension (e.g., a lateral dimension in a direction generally perpendicular to the direction between the input and output portions) that is (e.g., substantially, e.g., significantly) larger than a (e.g., lateral) dimension of the cavity. Thus, preferably, the walls of the body are thicker than one or more (e.g., all) of the dimensions of the cavity (e.g., the width (e.g., diameter) of the input portion, e.g., the width (e.g., diameter) of the output portion, e.g., the largest dimension). This makes it easier to control the boundary conditions of the shock wave as it passes through the cavity.

[0018] In an embodiment, the cavity (e.g., a portion thereof) comprises a frustum, e.g., the body is formed so as to define a frustum-shaped cavity, and thus preferably a cross-section of the cavity (e.g., in a plane parallel to the direction between the input and output) has straight sides (walls), e.g., the cross-section is symmetrical (in that plane).

[0019] The frustum may comprise any suitable and desired type of frustum. In an embodiment, the cavity comprises a truncated cone. Preferably, the cavity is therefore rotationally symmetric about an axis passing through the cavity. Preferably, the axis of the body or cavity is parallel to the direction between the input and output portions.

[0020] In embodiments, (the cross section and / or wall of) the cavity comprises two or more portions at different angles relative to the axis of the cavity (e.g., an axis about which the cavity is rotationally symmetric, e.g., parallel to the direction between the input and output). Thus, for example, the cavity may comprise two or more frustum shapes (e.g., for each pair of consecutive frustum shapes, the output of one frustum shape coincides with the input of the other frustum shape), with the two or more frustum shapes having sidewalls at different angles relative to the axis of the cavity. Providing different angles for portions of the cavity may facilitate steering an input shock wave in a particular manner, for example, accelerating the input shock wave from the input to the output.

[0021] In embodiments where the cavity has three or more frustum-shaped sections, each section may be at a different angle relative to each of the other sections, although two or more sections may be at the same angle with one or more intermediate sections of the cavity at a different angle.

[0022] In embodiments, instead of or in addition to a cavity having one or more straight lateral portions (in cross section), the cavity may have a cross section with one or more portions having curved walls. For example, the cavity may have a flared (e.g., conical) frustum shape, and the cavity walls are curved (e.g., elliptically). These types of shapes may tend to provide greater uniformity of the shock front and shock shape at the output.

[0023] In an embodiment, the amplifier comprises one or more impedance matching layers that facilitate coupling of energy between different layers of material. An impedance matching layer may comprise an (intermediate) layer of material disposed between two other materials, the impedance matching layer being composed of a material that has a shock impedance that is between the shock impedances of the two other materials.

[0024] For example, a layer of copper may be provided between a layer of aluminum and a layer of tantalum. In embodiments, the impedance matching layer may comprise multiple materials arranged in (e.g., parallel) layers such that the shock impedance varies (e.g., incrementally) between the layers.

[0025] In embodiments, the amplifier includes an input impedance matching layer adjacent to (e.g., extending across) the input of the cavity (e.g., its opening). The input impedance matching layer may facilitate improving the transfer of energy (e.g., from an incident projectile) into the second material, for example, by facilitating a reduction in the reflection component of the input shock wave from the surface of the second material. Thus, the input impedance matching layer may facilitate coupling of the input shock wave into the cavity.

[0026] In an embodiment, the input impedance matching layer comprises a planar layer. The input impedance matching layer may comprise (e.g., consist of) a material having a shock impedance greater than the shock impedance of the second material, e.g., a material having a shock impedance lower than the first material, e.g., a material having a shock impedance between the shock impedances of the first and second materials.

[0027] In an embodiment, the shock impedance of the input impedance matching layer is between the shock impedance of (the material of) an impacting projectile configured to generate an input shock wave (e.g., upon impact with the amplifier) and the shock impedance of the second material.

[0028] In embodiments, the amplifier includes an output impedance matching layer adjacent to (e.g., extending across) the output of the cavity (e.g., its opening). The output impedance matching layer may facilitate improving the transfer of energy from the cavity (e.g., the second material) by facilitating a reduction in the reflection component of the shock wave as it exits the cavity, e.g., from the output surface of the second material. Thus, the output impedance matching layer may facilitate coupling of the shock wave outside the cavity.

[0029] In an embodiment, the output impedance matching layer comprises a planar layer. The output impedance matching layer may comprise (e.g., consist of) a material having a shock impedance less than that of a second material, e.g., a material having a shock impedance greater than that of the material (e.g., fuel or target) on which the output shock wave is incident, e.g., a material having a shock impedance between the shock impedance of the second material and the shock impedance of the material (e.g., fuel or target) on which the output shock wave is incident. In an embodiment, the output impedance matching layer comprises polymethylpentene, e.g., TPX(RTM).

[0030] In an embodiment, the cavity is partially filled with the second material, i.e., the second material does not (completely) fill the cavity. Thus, in an embodiment, the cavity comprises a space between the input of the cavity and (the input face of) the second material. Depending on the size and / or shape of an incident projectile that may be used to generate an input shock wave, providing a gap in the cavity between the input (e.g., opening) and the second material may allow the projectile to, for example, directly impact the body of the amplifier (e.g., the wall of its cavity) before impacting the second material. This may generate a transverse shock wave inside the projectile, which may then be transmitted into the cavity.

[0031] Transverse shock waves within the projectile may tend to impart transverse focusing within the projectile, which in turn has the effect of causing shock waves transmitted into the cavity to be more focused towards the central axis of the cavity.

[0032] This is regarded as novel and inventive in its own right and therefore viewed from a further aspect the present invention provides a system for generating a localized concentration of energy, the system comprising: an amplifier for manipulating the input shock wave, the amplifier comprising: a body comprising a first material; the body defining a cavity for manipulating the input shock wave to generate a manipulated shock wave; The cavity is an input section that receives the input shock wave incident on the amplifier; an output section that outputs the manipulation shock wave from the cavity; Equipped with the cavity contains a second material having a shock impedance lower than the shock impedance of the first material; the cavity having a space between the input of the cavity and an input surface of the second material; The system further comprises a target configured to contain a fuel; The amplifier and the target are configured to be positioned such that the manipulation shock wave is output from the amplifier and impinges on the target.

[0033] It should be appreciated that this aspect may (and preferably does) include one or more (e.g., all) of the preferred and optional features disclosed herein, e.g., as applicable with respect to other aspects and embodiments of the invention.

[0034] The space between the input of the cavity and (the input surface of) the second material may be filled with any suitable and desired material. In one embodiment, the space is a vacuum. In one embodiment, the space is filled with a gas. The gas may consist of any suitable and desired gas.

[0035] In an embodiment, the cavity contains multiple (e.g., parallel) layers, one or more of which comprise (e.g., consist of) the second material. Preferably, the layers are parallel to the input and / or output (e.g., opening) of the cavity, e.g., perpendicular to the direction between the input and output. Thus, the layers are preferably perpendicular to the direction in which an input shock wave is arranged to propagate incident on the amplifier.

[0036] The presence of multiple layers facilitates the superposition of components of the input shock wave reflected from the boundaries between layers, which in turn facilitates amplification of the shock wave strength between the input and output sections of the cavity.

[0037] This is regarded as novel and inventive in its own right and therefore viewed from a further aspect the present invention provides a system for generating a localized concentration of energy, the system comprising: an amplifier for manipulating the input shock wave, the amplifier comprising: a body comprising a first material; the body defining a cavity for manipulating the input shock wave to generate a manipulated shock wave; The cavity is an input section that receives the input shock wave incident on the amplifier; an output section that outputs the manipulation shock wave from the cavity; a plurality of (e.g., parallel) layers between the input and output sections; Equipped with the plurality of layers includes one or more layers comprising a second material having a shock impedance lower than a shock impedance of the first material; The system further comprises a target configured to contain a fuel; The amplifier and the target are configured to be positioned such that the manipulation shock wave is output from the amplifier and impinges on the target.

[0038] It should be appreciated that this aspect may (and preferably does) include one or more (e.g., all) of the preferred and optional features disclosed herein, e.g., as applicable with respect to other aspects and embodiments of the invention. Thus, for example, the layers are preferably parallel to the input and / or output (e.g., openings) of the cavity, e.g., perpendicular to the direction between the input and output. Preferably, the body is formed such that the cross-sectional area of the input is greater than the cross-sectional area of the output.

[0039] In an embodiment, the plurality of layers comprises at least one first layer and at least one second layer, wherein the at least one first layer comprises (e.g., consists of) a third material and the at least one second layer comprises (e.g., consists of) a second material, In an embodiment, the third material has a higher shock impedance than the shock impedance of the second material.

[0040] In embodiments, the third material is (the same as) the first material. Thus, in these embodiments, the plurality of layers comprises at least one first layer and at least one second layer, wherein at least one first layer comprises (e.g., consists of) the first material and at least one second layer comprises (e.g., consists of) the second material.

[0041] In embodiments, the second material may be a solid, liquid, or gas. In embodiments, one or more of the second layers may be a vacuum.

[0042] In an embodiment, the plurality of layers comprises a plurality of first layers and / or a plurality of second layers, the plurality of layers alternating between first layers and second layers, e.g., (each of one or more of) a first layer adjacent to (sandwiched between) two second layers and / or (each of one or more of) a second layer adjacent to (sandwiched between) two first layers.

[0043] In embodiments in which the plurality of layers comprises a plurality of first layers and / or a plurality of second layers, each of the first layers may comprise (e.g., consist of) the same (e.g., third) material and / or each of the second layers may comprise (e.g., consist of) the same (e.g., second) material, although in some embodiments, one or more of the plurality of first layers may comprise (e.g., consist of) a material that is different from the third material and / or one or more of the plurality of second layers may comprise (e.g., consist of) a material that is different from the second material.

[0044] In embodiments, one or more of the first layers and / or one or more of the second layers may be compound layers, such that the layer comprises (e.g., consists of) sublayers, which may be made of different materials (e.g., different materials from the other sublayers and / or different materials from the second and third materials).

[0045] The multiple layers can have any suitable and desired thickness (the dimension perpendicular to the plane in which the layers extend and are parallel). For example, each of the multiple layers has the same thickness. In embodiments, the multiple layers (e.g., each of them) have different thicknesses. In embodiments in which the multiple layers include at least one first layer and at least one second layer, preferably, one or more (e.g., all) (e.g., each) of the at least one second layer has a thickness that is greater than the thickness of one or more (e.g., all) (e.g., each) of the at least one first layer.

[0046] In embodiments where the plurality of layers comprises a plurality of first layers and / or a plurality of second layers, each of the plurality of first layers may have the same thickness and / or each of the plurality of second layers may have the same thickness, and preferably, (e.g., each of) the plurality of second layers has a thickness greater than (e.g., each of) the thickness of the plurality of first layers. In embodiments, the thicknesses of the plurality of first layers vary among the first layers. In embodiments, the thicknesses of the plurality of second layers vary among the second layers. In embodiments, the thicknesses of the plurality of first layers decrease (progressively) from the input section to the output section. In embodiments, the thicknesses of the plurality of second layers decrease (progressively) from the input section to the output section.

[0047] In an embodiment, the second material may extend (fill) across (the width of) the cavity, ie in a direction perpendicular to the direction from the input to the output.

[0048] In embodiments, when a cavity accommodates multiple layers, one or more (e.g., all) of the layers extend across (the width of) the cavity (i.e., in the plane of the layers in a direction perpendicular to the input-to-output direction). For example, one or more (e.g., all) of the first layer and / or one or more (e.g., all) of the second layer may extend across the cavity.

[0049] In an embodiment, the cavity comprises a gap between the second material and the body of the amplifier, i.e., between the second material and the walls of the cavity, so that the second material can be spaced apart from the body of the amplifier, i.e., from the walls of the cavity.

[0050] In embodiments, when the cavity contains multiple layers, one or more (e.g., all) of the layers are spaced apart from the amplifier body, i.e., from the cavity walls. In embodiments, the cavity includes a gap between the multiple layers and the amplifier body, i.e., between the multiple layers and the cavity walls. Thus, in these embodiments, all of the multiple layers are spaced apart from the amplifier body.

[0051] When the cavity comprises a gap adjacent to the wall of the cavity, the gap may be filled with (e.g., be or consist of) a vacuum. In embodiments, the gap comprises a buffer layer (e.g., comprising (e.g., consisting of) a fourth material) adjacent to the wall of the cavity. Thus, (the wall of) the cavity may be juxtaposed to the buffer layer. Similarly, the fourth material may be located between the second material and the body of the amplifier and / or between one or more of the plurality of layers and the body of the amplifier.

[0052] The gap and / or buffer layer may cause the shock waves to tend to reflect off the cavity walls, reducing their coupling into the body of the amplifier, for example, and instead concentrating the shock waves towards the output of the cavity.

[0053] Preferably, the fourth material has a shock impedance lower than the shock impedance of the first material. In an embodiment, the fourth material has a shock impedance between the shock impedances of the first material and the second material.

[0054] In embodiments, the gap or buffer layer has a constant thickness (perpendicular to the walls of the cavity). In embodiments, the gap or buffer layer has a variable thickness. For example, the thickness of the buffer layer may vary (e.g., increase or decrease) from the input to the output of the cavity.

[0055] The various materials described herein (i.e., first and second materials, etc.) can comprise any suitable and desired material. In embodiments, the first material is (e.g., consists of) a solid. In embodiments, the first material is (e.g., consists of) a heavy (e.g., transition) metal, such as tantalum, platinum, tungsten, steel, or copper.

[0056] In embodiments, the second material is a solid (e.g., consists of a solid). In embodiments, the second material is a polymer, e.g., a thermopolymer, such as polymethyl methacrylate (PMMA) (e.g., consists of these polymers). In embodiments, the second material can be (e.g., can consist of) a liquid, e.g., water, ethanol, or oil. In embodiments where the plurality of layers comprises a plurality of second layers, one or more of the plurality of second layers can be (e.g., can consist of) a gas or a vacuum.

[0057] In an embodiment, the cavity comprises a first sub-cavity and a second sub-cavity (each) disposed between the input of the cavity and the output of the cavity, the first sub-cavity comprising an input and an output, the second sub-cavity comprising an input and an output, and the output of the first sub-cavity being coupled to the input of the second sub-cavity. Thus, a cavity may be formed having two (or more) sub-cavities, the first sub-cavity being disposed proximate the input of the cavity and the second sub-cavity being disposed proximate the output of the cavity.

[0058] This is regarded as novel and inventive in its own right and therefore viewed from a further aspect the present invention provides a system for generating a localized concentration of energy, the system comprising: an amplifier for manipulating the input shock wave, the amplifier comprising: a body comprising a first material; the body defining a cavity for manipulating the input shock wave to generate a manipulated shock wave; The cavity is an input section that receives the input shock wave incident on the amplifier; an output section that outputs the manipulation shock wave from the cavity; a first sub-cavity and a second sub-cavity disposed between the input of the cavity and the output of the cavity; Equipped with the first sub-cavity has an input portion and an output portion, and the second sub-cavity has an input portion and an output portion; the output of the first sub-cavity is coupled to the input of the second sub-cavity; The system further comprises a target configured to contain a fuel; The amplifier and the target are configured to be positioned such that the manipulation shock wave is output from the amplifier and impinges on the target.

[0059] It should be appreciated that this aspect may (and preferably does) include one or more (e.g., all) of the preferred and optional features disclosed herein, e.g., as applicable with respect to other aspects and embodiments of the invention.

[0060] In an embodiment, the body is formed such that the cross-sectional area of the output of the first sub-cavity may be different (different size) than the cross-sectional area of the input of the second sub-cavity, for example, the cross-sectional area of the output of the first sub-cavity may be larger than the cross-sectional area of the input of the second sub-cavity.

[0061] However, in a preferred embodiment, the body is formed such that the cross-sectional area of the output of the first subcavity is less than the cross-sectional area of the input of the second subcavity. Forming the cavity in this manner to provide multiple subcavities facilitates at least partial recapture of a manipulation shock wave output from one (e.g., a first) subcavity by the input of a subsequent (e.g., a second) subcavity. This may allow the shock wave to be further manipulated (e.g., focused) by the subsequent subcavity. This tends to reduce the energy of the input shock wave dissipated within the body of the amplifier, and thus tends to increase the energy transferred in the manipulation shock wave output from the cavity.

[0062] Preferably, the input of the first subcavity has a cross-sectional area greater than the cross-sectional area of the output of the first subcavity. Preferably, the input of the second subcavity has a cross-sectional area greater than the cross-sectional area of the output of the second subcavity. Thus, both of the subcavities have cross-sectional areas that decrease from their respective inputs to their outputs, and the cross-sectional area increases from the output of the first subcavity to the input of the second subcavity.

[0063] In an embodiment, the cavity comprises a plurality of sub-cavities, each sub-cavity comprising an input and an output, the output of each sub-cavity (away from the output of the sub-cavity proximal to the output of the cavity) being coupled to the input of the subsequent sub-cavity (in the direction from the input to the output of the cavity), and the body being formed such that the cross-sectional area of the output of each sub-cavity (away from the output of the sub-cavity proximal to the output of the cavity) is less than the cross-sectional area of the input of the subsequent sub-cavity.

[0064] Thus, preferably, the cavity has a plurality of connected sub-cavities along the direction from the cavity input to the cavity output. Preferably, the output of each (e.g., first) sub-cavity completely overlaps (enters) the input of the subsequent (e.g., second) sub-cavity. Thus, in an embodiment, the wall of the cavity comprises inwardly protruding portions to define the (inputs and outputs of) the sub-cavities.

[0065] In an embodiment, the cavity includes a (e.g., first) layer between the first and second subcavities, e.g., the (e.g., first) layer extends across the output of the first subcavity. If there are multiple subcavities, the cavity may include a first layer between (e.g., each of) adjacent subcavities. Separating the subcavities with a first layer may facilitate shock wave coupling between the subcavities.

[0066] Viewed from a further aspect, the present invention provides a system for generating a localized concentration of energy, the system comprising: an amplifier for manipulating the input shock wave, the amplifier comprising: an input surface for receiving the input shock wave incident on the amplifier; an output surface for outputting the manipulation shock wave from the amplifier; a plurality of (e.g., parallel) layers between the input surface and the output surface; Equipped with The system further comprises a target configured to contain a fuel; The amplifier and the target are configured to be positioned such that the manipulation shock wave is output from the amplifier and impinges on the target.

[0067] It should be appreciated that this aspect may (and preferably does) include one or more (e.g., all) of the preferred and optional features disclosed herein, as applicable, for example, with respect to other aspects and embodiments of the invention. For example, one or more (e.g., all) of the preferred and optional features outlined herein with respect to multiple layers may equally apply to this aspect of the invention.

[0068] In embodiments, any of the systems disclosed herein may include a mechanism for generating a shock wave that is incident on the amplifier.

[0069] In an embodiment, the mechanism for generating the shock wave comprises a mechanism configured to strike a projectile into an amplifier.

[0070] In an embodiment, the mechanism for generating the shock wave comprises an explosively powered mechanism, such as a gas gun, configured to fire a projectile into the amplifier.

[0071] In embodiments, the mechanism for generating the shock waves comprises an electromagnetic mechanism, such as a pulsed power machine, configured to use electromagnetic force to launch the projectile into the amplifier. For example, the mechanism may comprise a pulsed power magnetically driven plate flyer configured to launch the projectile into the amplifier.

[0072] In embodiments, the shock wave generating (e.g., electromagnetic) mechanism comprises an electromagnetic direct drive mechanism configured to generate a Lorentz force in an electrode adjacent to the amplifier, in such embodiments, the Lorentz force generates a shock wave in the electrode that is transmitted to the input of the amplifier.

[0073] In embodiments, the mechanism for generating the shock waves comprises a laser drive mechanism. The mechanism may comprise an ablator layer adjacent to the input of the amplifier cavity and one or more lasers configured to ablate the ablator layer to form shock waves in the amplifier cavity. In embodiments, the laser is incident directly on the ablator layer. In embodiments, the laser forms x-rays incident on the cavity surface that illuminate the ablator material and cause it to ablate.

[0074] In an embodiment, the target comprises a chamber configured to contain a fuel.

[0075] In embodiments, the chamber is configured to contain a gaseous fuel. In such embodiments, the chamber may be airtight. In embodiments, the fuel is a liquid, and thus the chamber may be configured to contain (e.g., only) a liquid fuel. In embodiments, the fuel is a solid, and thus the chamber may be configured to contain (e.g., only) a solid fuel.

[0076] In embodiments, the target is positioned to further manipulate the manipulated shock wave output from the amplifier, hi embodiments, the target may comprise a (e.g., conical) recess configured to direct the shock wave to an apex of the recess.

[0077] In an embodiment, the amplifier and target abut, eg, at least a portion of the amplifier abuts at least a portion of the target (eg, at least a portion of the output face of the amplifier abuts at least a portion of the target).

[0078] In an embodiment, the amplifier and target are physically separated, ie, there is a space between the amplifier and the target, so that the amplifier and the target are not in (eg, direct) contact with each other.

[0079] In an embodiment, the system comprises a mount configured to hold the amplifier and the target in position relative to each other, hi an embodiment, the mount comprises a clamp.

[0080] Viewed from a further aspect, the present invention provides a method of generating a localized concentration of energy using a system according to any one of the aspects or embodiments described herein, the method comprising: generating a shock wave to be incident on the amplifier; manipulating the shock waves with the amplifier; directing the manipulation shock wave at the target; Equipped with.

[0081] It should be appreciated that this aspect may (and preferably does) include one or more (e.g., all) of the preferred and optional features disclosed herein, e.g., as applicable with respect to other aspects and embodiments of the invention.

[0082] As used herein, the term "shock impedance" should be understood to mean "the pressure that must be exerted on a medium to give a portion of the medium a unit particle velocity" (Henderson, "On the refraction of shock waves," Journal of Fluid Mechanics, Vol. 198, January 1989, pp. 365-386), which is equal to the product of the shock velocity and the density of the non-shocked material.

[0083] It should be understood that the input shock wave may be formed outside the cavity and propagate into the input of the cavity, but may additionally or alternatively be generated within the amplifier, for example, by the amplifier being struck (e.g., by a projectile). Both alternatives are encompassed by the term "input shock wave."

[0084] Embodiments of the system may be suitable for manipulating (e.g., amplifying) shock waves to generate localized energy concentrations for the purpose of creating conditions suitable for nuclear fusion in a target. Accordingly, the target may contain (e.g., be configured to contain) a fusion fuel, such as hydrogen, deuterium, and / or tritium, in liquid, solid, and / or gas form. However, the system is not limited thereto and may be used in other applications in which the target contains fuel (e.g., of a different type). [Brief explanation of the drawings]

[0085] [Figure 1] 1 shows a schematic diagram of an apparatus according to an embodiment of the present invention. [Figure 2a] 10A-10C illustrate four successive stages of a shock wave's interaction with a device according to another embodiment of the present invention. [Figure 2b] 10A-10C illustrate four successive stages of a shock wave's interaction with a device according to another embodiment of the present invention. [Figure 2c] 10A-10C illustrate four successive stages of a shock wave's interaction with a device according to another embodiment of the present invention. [Figure 2d] 10A-10C illustrate four successive stages of a shock wave's interaction with a device according to another embodiment of the present invention. [Figure 3] 1 shows a longitudinal cross section through an exemplary amplifier. [Figure 4a] 4 shows one of six successive stages of the shock wave's interaction with the amplifier of FIG. 3. [Figure 4b] 4 shows one of six successive stages of the shock wave's interaction with the amplifier of FIG. 3. [Figure 4c] 4 shows one of six successive stages of the shock wave's interaction with the amplifier of FIG. 3. [Figure 4d] 4 shows one of six successive stages of the shock wave's interaction with the amplifier of FIG. 3. [Figure 4e] 4 shows one of six successive stages of the shock wave's interaction with the amplifier of FIG. 3. [Figure 4f] 4 shows one of six successive stages of the shock wave's interaction with the amplifier of FIG. 3. [Figure 5] A longitudinal section through the target is shown. [Figure 6] 6 shows a modification of the target of FIG. 5. [Figure 7] 6 shows a modification of the target of FIG. 5. [Figure 8] 6 shows a modification of the target of FIG. 5. [Figure 9] 6 shows a modification of the target of FIG. 5. [Figure 10] 6 shows a modification of the target of FIG. 5. [Figure 11] 10 shows a longitudinal section through an alternative target. [Figure 12] 12 shows a modification of the target of FIG. [Figure 13] 1 shows a longitudinal cross section through another exemplary amplifier. DETAILED DESCRIPTION OF THE INVENTION

[0086] Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0087] 1 shows a schematic diagram of an arrangement according to an embodiment of the present invention, comprising an amplifier 2 and a target 4. The target 4 is comprised of a solid medium 7 and defines a pocket 8 configured to contain a fusion fuel such as liquid deuterium, solid deuterium, or deuterium gas.

[0088] 1 shows a generally planar projectile 6. In the illustrated embodiment, the projectile 6 is a flat disk, although other projectiles may be used. The apparatus also includes a mount 10 that supports both the amplifier 2 and the target 4. The mount 10 is positioned to support the amplifier 2 and the target 4 such that the amplifier 2 is disposed between the projectile 6 and the target 4. In this manner, the projectile 6 strikes the amplifier 2.

[0089] The operation of this embodiment will now be described with particular reference to the four successive stages shown in Figures 2a to 2d.

[0090] First, a projectile 6 strikes the amplifier 2. The projectile 6 may be powered (for example) by a light gas gun or a mechanically or magnetically driven plate flyer with pulsed power. As the projectile 6 strikes the amplifier 2, a planar shock wave 12 is generated in the amplifier 2, as can be seen in FIG. 2a. As can be seen in FIG. 2b, the shock wave 12 propagates through the amplifier 2, with the velocity, pressure, and shape of the shock wave 12 being manipulated by the internal design of the amplifier 2.

[0091] In Figure 2c, shock wave 12 emerges from amplifier 2 and impinges on target 4. As can be seen in Figure 2d, as shock wave 12 propagates through target 4, it impinges on fuel target pocket 8. This compresses the fuel within fuel target pocket 8, resulting in intense localized heating that may be sufficient to initiate fusion.

[0092] By providing the amplifier 2 between the projectile 6 and the target 4, the shock wave pressure pulse emitted from the amplifier 2 is modified and directed by the amplifier 2 to have an enhanced pressure profile, velocity and duration.

[0093] Additionally, the independent provision of amplifier 2 and target 4 provides a "plug and play" system where different amplifier designs can be used with different target designs to achieve specific impact conditions, and for experimental purposes, alternate targets / amplifiers can be tried without having to reconfigure the entire system.

[0094] Figure 3 shows a longitudinal cross section through amplifier 2. It should be understood that the amplifier 2 shown in Figure 3 is merely exemplary and that other amplifier designs may be used in accordance with embodiments of the present invention.

[0095] The amplifier 2 comprises a body 33 defining a hollow, frustum-shaped cavity 35. The body 33 is constructed of a material having a high shock impedance. In the illustrated embodiment, the body 33 is constructed of a high shock impedance material such as tantalum, platinum, tungsten, steel, copper, or other (e.g., heavy) metal. The cavity 35 contains a material (cavity filler) 37 having a low shock impedance. The cavity filler 37 has a shock impedance lower than the shock impedance of the body 33. In the illustrated embodiment, the cavity filler 37 is polymethyl methacrylate (PMMA), although other materials are contemplated, and the cavity filler 37 may be a solid, liquid, or gas.

[0096] Cavity 35 has an input portion 39 configured to receive shock waves and an output portion 311 configured to output the shock waves after they have propagated through amplifier 2. The cross-sectional area of input portion 39 is larger than the cross-sectional area of output portion 311.

[0097] 3 shows a longitudinal cross section, and in the illustrated embodiment, amplifier 2 is rotationally symmetric. It should be understood that the cavity 35 of amplifier 2 is thus formed as a truncated cone with an input radius that is larger than the output radius. Amplifier 2 has an input face 310 proximate the input 39 of cavity 35 and an output face 312 proximate the output 311 of cavity 35.

[0098] 3 illustrates an embodiment of amplifier 2 having an impedance matching layer 317 disposed on the input face 310 of amplifier 2. Impedance matching layer 317 is a planar layer of material having an impact impedance between the impact impedance of projectile 6 and the impact impedance of cavity filler 37. Impedance matching layer 317 improves coupling efficiency into amplifier 2 such that a greater percentage of the energy input into amplifier 2 by projectile 6 is transferred to cavity filler 37.

[0099] In embodiments, the impedance matching layer 317 may be constructed of a material with a variable impact impedance, such as a high-impedance foam. The initial impact strikes a relatively low-impedance material, but then compresses the foam such that the aftermath strikes a compressed, higher-impedance material. Such an impedance matching layer 317 may enable the use of low-impedance projectiles 6, as low-impedance projectiles may bond effectively to the foam.

[0100] The function of amplifier 2 will now be further explained with reference to Figures 4a-4e. Figures 4a-4e show a projectile 6 striking amplifier 2 shown in Figure 4a. Figure 4a shows projectile 6 striking impedance matching layer 317. In Figures 4b and 4c, the resulting shock wave 12 passes through impedance matching layer 317 and enters cavity filler 37. Pressure increases in amplifier 2 through shock wave reflection and superposition within cavity 35.

[0101] When an input shock enters cavity 35, as can be seen in Figure 4d, the input shock reflects from cavity wall 36 as an irregular shock reflection (Mach reflection), which propagates from cavity wall 36 and eventually overlaps with the central axis of cavity 35, as shown in Figures 4e and 4f.

[0102] This radially symmetric wave superposition about the central axis creates a high pressure point within the cavity fill 37, which expands and interacts with impinging Mach reflections, resulting in the generation of an axial quasi-planar Mach stem that propagates towards the output 311 of the cavity 35. This wave eventually reaches the output 311 of the cavity 35 and emerges from the amplifier 2 at a pressure higher than that of the original input shock wave 12.

[0103] 1, target 4 defines an internal chamber (pocket) 8 configured to contain fusion fuel. In other embodiments, chamber 8 may be formed as a depression in the surface of target 4. In such embodiments, the surface of the target may be covered with a coverslip to contain the fuel. Alternatively, if the target abuts an amplifier, a coverslip may not be necessary to contain the fuel.

[0104] 5 shows a longitudinal section through the target 54 defining a conical chamber 58. In the illustrated embodiment, the target is constructed of gold, although other materials such as platinum, tungsten, steel, or aluminum are also contemplated.

[0105] In use, chamber 58 contains a fusion fuel such as liquid deuterium, solid deuterium, or deuterium gas. Chamber 58 is sealed by a coverslip 53 that is placed on the surface of the target. When an actuation shock wave propagates into chamber 58, gas is forced to compress by the shock wave to point 59 in chamber 58.

[0106] Figure 6 shows a variation of the target shown in Figure 5. The target 64 defines a chamber 68 that is shaped as a sawtooth cone so that the walls of the chamber 68 are stepped. This sawtooth shape may help the shock wave capture and therefore compress the gaseous fuel.

[0107] FIG. 7 illustrates a variation of the target shown in FIG. 5. The target 74 defines a biconic chamber 78. The chamber 78 is shaped as a cone, with the chamber wall comprising two sections at different angles relative to the longitudinal axis of the chamber. In embodiments, three or more wall sections may be provided; for example, the chamber may be triconic. In embodiments, the chamber wall may be curved such that the chamber has a flared conical shape. In such a target, the compression of the gaseous fuel may be enhanced because the shape of the chamber further concentrates the shock wave after exiting the amplifier 2.

[0108] Figure 8 shows a variation of the target shown in Figure 5. The chamber 88 comprises two sections. The first section 81 is proximal to the output of the amplifier 2 and is bowl-shaped. The second section 82 is conical. Both the first and second sections share the same central axis. The chamber 88 helps prevent jetting and forms a converging impulse above the second section 82, compressing the gaseous fuel into the second section 82.

[0109] Figure 9 shows a variation of the target shown in Figure 5. The chamber 98 of the target 94 has stepped, curved chamber walls. The chamber 98 helps prevent jetting, forming a series of converging impingements. The curved surface also blunts the jetting of the coverslip 53.

[0110] Figure 10 shows a variation of the target shown in Figure 5. The chamber 108 of the target 104 is formed as a cone with walls that gradually recede proximate the apex of the cone toward the base of the cone, with the apex of the inverted cone aligned with the central axis of the chamber 108. As can be seen in Figure 10, a longitudinal cross section along the chamber 108 generally forms a curved "W" shape. The inverted cone portion of the chamber wall guides the shock wave toward the central convergence, providing a higher degree of convergence.

[0111] In all respects except as expressly stated, the configuration of the modified targets 64, 74, 84, 94, 104 described above is as described in relation to target 54.

[0112] FIG. 11 illustrates an alternative target design. It shows a longitudinal cross section through a target 114 that defines a frusto-conical chamber 118. The target 114 is composed of a high-impedance material (solid medium) 7, which in the illustrated embodiment is tantalum. The chamber 118 is filled with a material having a lower impedance than the target material. In the illustrated embodiment, the chamber fill is polymethyl methacrylate (PMMA). The chamber fill defines an inverted-cone-shaped subchamber 112 located at the narrow end of the chamber 118. In use, the subchamber 112 contains a fusion fuel, such as liquid deuterium, solid deuterium, or deuterium gas. As an operating shock wave propagates through the chamber fill and into the subchamber 112, the fuel is compressed by the shock wave.

[0113] Figure 12 shows a variation of the target of Figure 11. In target 124, chamber 128 is conical, and subchamber 122 has an arrowhead cross section such that subchamber 122 is formed as a cone with a conical recess at its base. The point of the cone of subchamber 122 is proximate to the apex of the cone of chamber 128. In use, impacts will be delivered to points at the base of the arrowhead (or, in a three-dimensional view, the periphery of the base of the cone), preheating and precompressing the fuel before the impacts converge at the tip of subchamber 122 and impact the preheated, partially collapsed fuel.

[0114] 13 shows an amplifier 102 according to another embodiment of the present invention. The amplifier 102 comprises a body 133 constructed from a series of parallel layers. The layers include a low shock impedance layer 130 constructed from a low shock impedance material such as PMMA or epoxy resin, and a high shock impedance layer 132 constructed from a high shock impedance material such as tantalum, tungsten, steel, copper or platinum. As a minimum requirement, the high shock impedance layer 132 is constructed from a material that has a higher shock impedance than the material that constructs the low shock impedance layer.

[0115] The parallel layers alternate layer by layer from low shock impedance layers 130 to high shock impedance layers 132. In the illustrated embodiment, the input layers 134 that make up the input face 110 of the amplifier 102 are low shock impedance layers 130. This is because an input face 110 made up of high shock impedance layers 132 causes a greater proportion of the shock waves to be reflected by the input face 110 and thereby not transmitted into the amplifier 102. However, alternatives are contemplated.

[0116] In the illustrated embodiment, the thicknesses of the high shock impedance layers 132 and the low shock impedance layers 130 decrease progressively from the input face 110 to the output face, although in some embodiments, each of the high shock impedance layers 132 is of equal thickness. It should be understood that although the thickness may vary between layers, each individual layer has a uniform thickness across its width.

[0117] The layers are arranged so that shock waves generated at the input face 110 of the amplifier 102 of the stack reverberate within the stack as a result of reflections from the high shock impedance layer 132, resulting in regions of constructive and destructive interference as the shock waves pass through each other. As a shock passes from the low shock impedance layer 130 to the high shock impedance layer 132, part of the shock is transmitted into the high shock impedance layer 132 while part is reflected back into the low shock impedance layer 130.

[0118] The portion within the low shock impedance layer 130 accelerates as it travels through the previously shocked material, and the shock portion is then reflected from the boundary at the input of the low shock impedance layer. Because of its acceleration, the reflected portion eventually catches up with the portion of the shock that was originally transmitted into the high shock impedance layer 132. The configuration of the low shock impedance layer 130 and the high shock impedance layer 132 allows the amplifier 102 to be positioned such that multiple shock signatures overlap the output face 112 of the amplifier 102, creating a brief, high shock pressure condition that can be passed into a target adjacent the amplifier output face 112.

[0119] In the illustrated embodiment, all of the high shock impedance layers 132 are composed of the same material, and all of the low shock impedance layers 130 are composed of the same material. In embodiments, different low shock impedance materials may be used for different low shock impedance layers 130, and different high shock impedance materials may be used for different high shock impedance layers 132.

[0120] In each of the above-described embodiments, the drawings shown are longitudinal cross sections through the three-dimensional volume of gas and target surface, and therefore they illustrate rotationally symmetric embodiments, although this is not required by the invention.

Claims

1. 1. A system for generating a localized concentration of energy, comprising: an amplifier arranged to manipulate one or more of the velocity, pressure or shape of the input shock wave, the amplifier comprising: a body comprising a first material; the body defining a cavity for manipulating the input shock wave to generate a manipulated shock wave; The cavity is an input section that receives the input shock wave incident on the amplifier; an output unit that outputs an operation shock wave; Equipped with The system further comprises a target configured to contain a fuel; The system is configured such that the amplifier and the target are positioned such that the manipulation shock wave is output from the amplifier and incident on the target.

2. The system of claim 1 , wherein the cavity contains a second material having a lower impact impedance than the first material.

3. 3. The system of claim 1, wherein the cross-sectional area of the input section is greater than the cross-sectional area of the output section.

4. The system of claim 1 , 2 or 3, wherein the cavity is frustum-shaped.

5. The system of claim 1 , wherein the cavity comprises a truncated cone.

6. The system of claim 1 , further comprising a mechanism for generating shock waves to be incident on the amplifier.

7. The system of claim 6 , wherein the mechanism for generating the shock wave comprises a mechanism arranged to strike a projectile at the amplifier.

8. The system of claim 6 or 7, wherein the mechanism comprises an electromagnetic mechanism.

9. 8. The system of claim 6 or 7, wherein the mechanism comprises an explosively powered mechanism.

10. The system of claim 6 , wherein the mechanism comprises an electromagnetic direct drive mechanism configured to generate a Lorentz force in an electrode adjacent to the amplifier.

11. 7. The system of claim 6, wherein the mechanism for generating the shock waves comprises an ablator layer adjacent the input of the amplifier cavity component and a laser drive mechanism comprising one or more lasers configured to ablate the ablator layer.

12. The system of claim 1 , wherein the target comprises a chamber configured to contain a fuel.

13. The system of claim 12 , wherein the chamber is configured to contain a gaseous fuel.

14. 14. The system of claim 1, wherein the target is positioned to further manipulate the manipulation shock wave output from the amplifier.

15. 15. The system of claim 1, wherein the amplifier and the target are in abutting contact.

16. 15. The system of claim 1, wherein the amplifier and the target are physically separated.

17. 17. The system of claim 1, comprising a mount configured to hold the amplifier and the target in position relative to each other.

18. 1. A system for generating a localized concentration of energy, comprising: an amplifier for manipulating the input shock wave, the amplifier comprising: a body comprising a first material; the body defining a cavity for manipulating the input shock wave to generate a manipulated shock wave; The cavity is an input section that receives the input shock wave incident on the amplifier; an output section that outputs the manipulation shock wave from the cavity; Equipped with the cavity contains a second material having a shock impedance lower than the shock impedance of the first material; the cavity having a space between the input of the cavity and an input surface of the second material; The system further comprises a target configured to contain a fuel; The system is configured such that the amplifier and the target are positioned such that the manipulation shock wave is output from the amplifier and incident on the target.

19. 1. A system for generating a localized concentration of energy, comprising: an amplifier for manipulating the input shock wave, the amplifier comprising: a body comprising a first material; the body defining a cavity for manipulating the input shock wave to generate a manipulated shock wave; The cavity is an input section that receives the input shock wave incident on the amplifier; an output section that outputs the manipulation shock wave from the cavity; a plurality of layers between the input and output sections; Equipped with the plurality of layers includes one or more layers comprising a second material having a shock impedance lower than a shock impedance of the first material; The system further comprises a target configured to contain a fuel; The system is configured such that the amplifier and the target are positioned such that the manipulation shock wave is output from the amplifier and incident on the target.

20. 1. A system for generating a localized concentration of energy, comprising: an amplifier for manipulating the input shock wave, the amplifier comprising: a body comprising a first material; the body defining a cavity for manipulating the input shock wave to generate a manipulated shock wave; The cavity is an input section that receives the input shock wave incident on the amplifier; an output section that outputs the manipulation shock wave from the cavity; a first sub-cavity and a second sub-cavity disposed between the input of the cavity and the output of the cavity; Equipped with the first sub-cavity having an input portion and an output portion, and the second sub-cavity having an input portion and an output portion; the output of the first sub-cavity is coupled to the input of the second sub-cavity; The system further comprises a target configured to contain a fuel; The system is configured such that the amplifier and the target are positioned such that the manipulation shock wave is output from the amplifier and incident on the target.

21. 1. A system for generating a localized concentration of energy, comprising: an amplifier for manipulating the input shock wave, the amplifier comprising: an input surface for receiving the input shock wave incident on the amplifier; an output surface for outputting a manipulation shock wave from the amplifier; a plurality of layers between the input surface and the output surface; Equipped with The system further comprises a target configured to contain a fuel; The system is configured such that the amplifier and the target are positioned such that the manipulation shock wave is output from the amplifier and incident on the target.

22. 22. A method of generating a localized concentration of energy using a system according to any one of claims 1 to 21, comprising the steps of: generating a shock wave to be incident on the amplifier; manipulating the shock waves with the amplifier; directing the manipulation shock wave at the target; A method for providing the above.

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