Component for compressing matter

Abstract

A component (1) for compressing matter using an input shockwave. The component includes: a body (2) having a recess wall (6) defining a recess (4), an input (10) for inputting the input shockwave into the component, and a focussing element (9) within the recess (4). The focussing element (9) defines a volume (12) configured to contain the matter to be compressed. The recess wall is configured to reflect the input shockwave towards the focussing element. The focussing element is configured to focus the reflected shockwave onto the volume.

Description

[0001] Component for Compressing Matter

[0002] This invention relates to a component for compressing matter using an input shockwave, in particular to methods and apparatuses for compressing matter by producing high localised concentrations of energy by manipulating an input shockwave to produce a high pressure quasi-spherical shockwave incident on the matter to be compressed.

[0003] It has been shown in WO 2011 / 138622 that an interaction between a shockwave in a non-gaseous medium and a gaseous medium can generate a high speed transverse jet of the non-gaseous medium that moves through the gaseous medium. This results in the jet impacting on and trapping a volume of the gaseous medium, which gives rise to an intense concentration of energy within the gas.

[0004] The present invention aims to provide alternative techniques for producing localised energy concentrations.

[0005] When viewed from a first aspect, the invention provides a component for compressing matter using an input shockwave, the component comprising: a body comprising a recess wall defining a recess; an input for inputting the input shockwave into the component; and a focussing element within the recess; wherein the focussing element defines a volume configured to contain the matter to be compressed; wherein the recess wall is configured to reflect the input shockwave towards the focussing element; and wherein the focussing element is configured to focus the reflected shockwave onto the volume.

[0006] The invention thus provides a component that manipulates (e.g. focusses) an input shockwave to be incident upon a target volume within the component, when a shockwave is input into the component, causing localised concentration of energy to be generated at the target volume. The component includes a body comprising a recess that reflects portions of the input shockwave towards a focussing element that defines the target volume.

[0007] In use, the input shockwave is reflected from the (e.g. walls of the) recess towards the focussing element, and then propagates through the focussing element to the target volume. The (e.g. shape and / or materials of the) focussing element are designed to manipulate (e.g. focus, e.g. modify the shape and / or intensity of) the shockwave as it passes through the focussing element towards the target volume.

[0008] The body may be provided in any suitable and desired way. In some embodiments, the body comprises (e.g. is formed from, e.g. consists of) a first material. Preferably the body is a unitary body, e.g. formed from the first material. Thus preferably the body is formed as a single part.

[0009] The first material may comprise any suitable and desired material, in which a recess may be formed. Preferably the first material is a solid. Preferably the first material comprises (e.g. is formed from, e.g. consists of) a high shock-impedance material. Preferably the first material comprises (e.g. is formed from, e.g. consists of) a metal, e.g. a refractory metal, e.g. tantalum. The first material may comprise (e.g. be formed from, e.g. consists of) tungsten, steel, copper or other (e.g. heavy) metals. Such materials are resistant to high temperatures and pressures, have a high shock-impedance and hardness.

[0010] The body comprises (is shaped to define) a recess, e.g. in a surface of the body.

[0011] The recess may have any suitable and desired shape. In some embodiments the recess wall comprises a curved portion. In some embodiments the recess is concave. For example, the recess may have an opening (e.g. proximal to the input of the component) in an outer surface of the body that has a greater dimension (e.g. is wider) than a base of the recess.

[0012] In some embodiments the (e.g. wall defining the) recess is bowl-shaped, e.g. substantially hemispherical. This may help to spherically focus the input shockwave towards the focussing element and the target volume. In some embodiments the recess contains (e.g. is filled with) a second material (e.g. recess fill material) (e.g. that surrounds the focussing element). The second material is different to the (first material of the) body. Preferably the second material has a lower shock-impedance than the shock-impedance of the first material. In such embodiments, the second material is non-gaseous, e.g. non-fluid, e.g. solid.

[0013] Filling the recess with a material helps to support and position the focussing element within the recess. This may mean that it is not necessary to provide a separate support structure for the focussing element, which could interfere with the dynamics of the shockwave as it propagates through the component.

[0014] Filling the recess with a (second) material having a lower shock-impedance than the (first) material of the body helps to control the manipulation (e.g. focussing) of the shockwave as it propagates through the component, in particular the reflection of the shockwave from the walls of the recess, which may be enhanced by the difference in shock-impedance of the first and second materials.

[0015] The recess may be filled with any suitable and desired material. In some embodiments, the recess is filled with a polymer (e.g. polymethyl methacrylate (PM MA)), epoxy resin or low density foams.

[0016] The input of the component may be provided in any suitable and desired way, to input the shockwave into the component. For example, nature of the input may depend on how the shockwave is generated.

[0017] In some embodiments, the input of the component is provided by an outer surface of the body and / or the outer surface of the (e.g. second material in the) recess. Thus, the body and / or the (e.g. second material of the) recess may comprise (e.g. together form) an input face or (e.g. outer) layer (e.g. the input layer having an input face).An outer surface of the body and outer surface of the second material of the recess may be co-planar.

[0018] Preferably the input face or layer extends in one or more directions about (e.g. substantially perpendicular to) a central (longitudinal) axis of the (e.g. body of the) component. One or more (e.g. all) of the input face, the body, the recess, the focussing element and the component may be (e.g. rotationally) symmetrical about the central axis.

[0019] In use, the (e.g. input face or layer of the) input may be arranged to be impacted, e.g. by a projectile, e.g. directed along the central axis so to be incident upon the input (face or layer). Thus, in some embodiments, the input shockwave may be generated in the component, for example, by the (e.g. input face or layer of the) input (e.g. the body and / or the recess material) being struck or impacted (e.g. by a projectile). In some embodiments, the input shockwave may be generated externally from the component, and, e.g., be received by (e.g. be incident upon) the input of the component.

[0020] In some embodiments, the (e.g. input face or layer of the) input comprises a concave portion (when the input is viewed externally). In embodiments, the (e.g. entire) input face or layer is concave and, e.g., continuously curved. Such embodiments may be used with a projectile (e.g. having a substantially flat impacting surface) that is arranged to strike the (e.g. input of the) component to generate a shockwave having a curved shock-front in the (e.g. body and / or recess of the) component.

[0021] In some embodiments, the (e.g. input face or layer of the) input comprises a convex portion. In embodiments, the (e.g. entire) input face or layer is convex. Such embodiments may be configured to work with a projectile which strikes the (e.g. input of the) component to generate a shockwave. A convex input face may not help to curve the shockwave, but a convex input face may be less sensitive to projectile tilt (e.g. the projectile not being perfectly aligned with the input face) and so may be preferable to a concave face in systems where the angle of the projectile at the input is less predictable.

[0022] In some embodiments, the (e.g. input face or layer of the) input comprises a flat portion. In embodiments, the (e.g. entire) input face or layer is flat. Such embodiments may be used with a projectile having a curved (e.g. concave) impacting surface that is arranged to strike the (e.g. input of the) component to generate a shockwave having a curved shock-front in the (e.g. body and / or recess of the) component. In embodiments, the (e.g. input face or layer of the) input has a convex face. Such embodiments may be configured to be used with a projectile having a corresponding concave impacting surface which is arranged to strike the (e.g. input of the) component such that the impacting surface of the projectile and the input face are aligned (e.g. the impacting surface is complementary to the input face) when the projectile impacts the component. Such embodiments may help to increase the energy coupling from the projectile into the component.

[0023] Although some examples have been described herein, all possible input face and projectile impacting face convex / concave combinations are envisaged.

[0024] In some embodiments the component comprises at least one impedance matching layer adjacent to or at the input of the focussing portion. In some embodiments, the input (e.g. layer) of the focussing portion comprises the impedance matching layer.

[0025] Providing an impedance matching layer, e.g. matching the impedance of an incident projectile, may help to couple the incident shockwave into the (e.g. focussing portion of the) component. Thus, as outlined above in relation to the input of the focussing portion, the impedance matching layer may be arranged to be impacted by a projectile to generate the input shockwave.

[0026] Thus, in some embodiments, the input of the focussing portion is provided by (e.g. an outer surface of) the impedance matching layer, e.g. together with an outer surface of the body. In some embodiments, the impedance matching layer extends across the (e.g. input of the) focussing portion, e.g. between the wall(s) of the body (e.g. that form the recess). Thus, the body and / or the impedance matching layer may comprise (e.g. together form) an input face. An outer surface of the body and outer surface of the impedance matching layer may be co-planar.

[0027] The focussing element may be arranged within the recess in any suitable and desired way. When the recess contains (e.g. is filled with) a second material, preferably the focussing element is contained within (e.g. surrounded by) the second material. Preferably the second material and the focussing element are contiguous (e.g. over the majority or substantially all of the surface area of the focussing element), such that there is substantially no gap between the second material and the focussing element. Embedding the focussing element in the second material may help the shockwave to be transmitted from the second material into the target element.

[0028] In some embodiments, the (e.g. base of the) focussing element is spaced from the surface (e.g. wall (e.g. base)) defining the recess, such that some of the volume of the recess (e.g. the second material) is between the focussing element and the recess. In some embodiments, the (e.g. base of the) focussing element is in contact with the (e.g. wall (e.g. base) of the) recess, such that there is none of the recess (e.g. none of the second material) between the focussing element and the recess.

[0029] In some embodiments, the component comprises an (e.g. shaped) impedance matched element between the (e.g. base of the) focussing element and the surface (e.g. wall (e.g. base)) defining the recess. This may help to suppress the formation of a high pressure jet and thus help to concentrate the energy of the manipulated shockwave towards the target volume.

[0030] In some embodiments, the recess comprises a depression distal from the component input, e.g. on the opposite side of the focussing element from the input. This may help to suppress the formation of a high pressure jet and thus help to concentrate the energy of the manipulated shockwave towards the target volume.

[0031] In some embodiments, the focussing element has a shock-impedance that varies (e.g. changes continuously or discretely (in steps)) through the focussing element. This may help to couple the shockwave into the focussing element towards the target volume.

[0032] In some embodiments, the shock-impedance of the focussing element proximal to an outer surface of the focussing element is lower than the shock-impedance of the focussing element proximal to the target volume.

[0033] In some embodiments, the focussing element comprises a plurality of shells. Two or more of the plurality of shells may have a shock-impedance that is different from each other. The focussing element may comprise any suitable and desired number of shells. In some embodiments the focussing element comprises between one and thirty layers, e.g. between three and ten layers.

[0034] It may be that the shock-impedance of the shells of the two or more shells decreases progressively from an outer surface of the focussing element towards the volume, however, in some embodiments, the shock-impedance of the shells of the two or more shells increases progressively from an outer surface of the focussing element towards the volume. The focussing element may be configured as an impedance matching element. This helps to couple the input shockwave from the recess into the target volume through the focussing element. Furthermore, by increasing the shock-impedance progressively through the shells, the energy coupling between the shells may be improved, since no two adjacent shells need to have a large shock-impedance difference (that could cause reflections of the shockwave and thus energy loss).

[0035] In some embodiments, the plurality of shells comprises one or more first shells formed of (comprising or consisting of) a third material having a third shockimpedance, and one or more second shells formed of (comprising or consisting of) a fourth material having a shock-impedance that is lower than a shock-impedance of the third material.

[0036] Providing shells having different shock-impedances may cause the shockwave to be (at least partially) reflected from the boundaries between layers (e.g. at the boundaries between the fourth and third materials). This may help to superimpose components of the propagating shockwave within the focussing element, e.g. to amplify the intensity of the shockwave that is incident upon the target volume.

[0037] In some embodiments, the plurality of shells comprises a plurality of first shells and / or a plurality of second shells.

[0038] The first and second shells may be arranged in any suitable and desired way in the focussing element. In some embodiments, the one or more first shells and the one or more second shells are arranged to alternate between a first shell and a second shell (e.g. repeatedly when there are a plurality of first and / or second shells). Thus, preferably (each of one or more of) the first shell(s) is adjacent (sandwiched between) two second shells and / or (each of one or more of) the second shell(s) adjacent (sandwiched between) two first shells.

[0039] In embodiments, the focussing element is formed unitarily and has a shockimpedance that varies progressively from an outer surface of the focussing element towards the volume. This may help to couple the shockwave through the focussing element, as reflections between the boundaries of discrete shells may be eradicated.

[0040] The focussing element may comprise any suitable and desired shape. The focussing element may have a circular cross-section, e.g. in a plane parallel to (e.g. containing) the central axis of the component and / or in a plane perpendicular to the central axis of the component. The focussing element may be spherical.

[0041] In some embodiments the focussing element has an oval cross-section, e.g. in a plane parallel to (e.g. containing) the central axis of the component. Preferably the focussing element is rotationally symmetrical, e.g. about the central axis of the component.

[0042] Thus, in some embodiments, the focussing element is substantially ovoidal (egg- shaped). An ovoidal focussing element may help to further manipulate (e.g. focus) the shockwave as it propagates into the focussing element towards the target volume.

[0043] Preferably one end of the ovoidal focussing element is more tapered and the other end is more rounded. Preferably the focussing element has a maximum dimension (e.g. the longest dimension (major axis) of the ovoid) that is parallel (e.g. coaxial) with the central axis of the component. Preferably the more tapered end of the ovoid is proximal to the input of the component. Preferably the more rounded end of the ovoid is proximal to the base of the recess.

[0044] In embodiments, a central axis of the focussing element is co-axial with a central axis of the recess. In embodiments, the matter to be compressed comprises a fuel, e.g. a fusionable fuel (e.g. hydrogen, deuterium and / or tritium) such that the target volume is a fuel volume and the component is a component for compressing fuel. When fuel is present in the volume and an input shockwave is manipulated by the focussing element to produce a localised energy concentration at the volume, this may cause the fuel in the volume to collapse, creating high pressures and temperatures within the fuel, e.g. sufficient for initiating fusion.

[0045] In embodiments, the matter to be compressed may comprise a fuel-containing material. It will be understood that the term “fuel-containing material” refers to a material that is not solely fuel. Rather, a fuel-containing material comprises a material (e.g. a bulk or lattice material) that is not fuel, in or among which fuel is contained (e.g. as part of a mixture or compound). In embodiments, the fuelcontaining material comprises fuel that is (e.g. uniformly) dispersed throughout the material. In embodiments, the fuel-containing material comprises a non-localised fuel.

[0046] In some embodiments, the fuel-containing material is a compound, e.g. with the fuel ionically or covalently bonded in the compound. Thus, in some embodiments, the fuel-containing material comprises a hydride such as water, lithium hydride, aluminium hydride or ammonia. In some embodiments, the fuel-containing material comprises a deuteride such as deuterated water, lithium deuteride, aluminium deuteride or deuterated ammonia. In some embodiments, the fuel-containing material comprises a tritiide such as tritiated water, lithium tritiide, aluminium tritiide or tritiated ammonia.

[0047] In some embodiments, the fuel-containing material comprises a hydrocarbon (e.g. deuterated or tritiated hydrocarbon). It will be understood that in a (e.g. deuterated or tritiated) hydrocarbon (or other hydrogen, deuterium or tritium containing compound), the fuel is provided by the hydrogen, deuterium or tritium atoms or ions in the compound and the remaining atoms or ions are the bulk material.

[0048] In some embodiments, the fuel-containing material is a fuel-doped material, e.g. a material into which the fuel (e.g. fuel atoms or ions) replaces atoms or ions, for example, in the material, e.g. in a (e.g. crystalline) lattice. In some embodiments, the fuel-containing material comprises fuel-doped metal, such as hydrogen-doped palladium, hydrogen-doped aluminium, hydrogen-doped lithium, deuterium-doped palladium, deuterium-doped aluminium, deuterium-doped lithium, tritium-doped palladium, tritium-doped aluminium or tritium-doped lithium.

[0049] It will be understood that in a fuel-doped material, the fuel is provided by the dopant (e.g. the hydrogen, deuterium or tritium atoms or ions that are inserted into the material) and the remaining atoms or ions are the bulk (or lattice) material.

[0050] In some embodiments, the fuel-containing material is a mixture containing the fuel, e.g. the fuel may be located in interstitial gaps in the (e.g. bulk or lattice) material, such that the fuel-containing mixture is a mixture of the (e.g. bulk or lattice) material and the fuel.

[0051] In some embodiments, the fuel-containing material comprises a non-gaseous material, e.g. a liquid. In some embodiments, the fuel-containing material comprises a non-fluid material, such that it substantially holds its own shape (at normal temperatures and pressures). In some embodiments, the fuel-containing material comprises a semi-solid (e.g. a gel or foam) fuel-containing material. In some embodiments, the fuel-containing material comprises a solid fuel-containing material. In some embodiments the fuel-containing material comprises a fuelcontaining metal, e.g. fuel-containing palladium, aluminium or lithium.

[0052] The fuel may comprise any suitable and desired fuel. In some embodiments, the fuel comprises a fusionable fuel, e.g. hydrogen, deuterium and / or tritium. Thus, in some embodiments, the component is configured to manipulate the input shockwave to provide a localised concentration of energy within the target element that is suitable for initiating fusion, e.g. to generate a localised concentration of energy of sufficiently high temperature and / or pressure.

[0053] The invention also provides a method of compressing matter using an input shockwave and thus, from a further aspect, the invention provides a method of compressing matter using an input shockwave, the method comprising generating the input shockwave at an input of the component according to any one of the aspects or embodiments described herein.

[0054] It will 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. relating to other aspects and embodiments of the invention, as applicable.

[0055] For example, the method may comprise generating the input shockwave in the component, for example, by striking or impacting the (e.g. input face of the) input of the component (e.g. by a projectile). In some embodiments, the input shockwave may be generated externally from the component, and, e.g., be received by (e.g. be incident upon) the input of the component. Thus the method may comprise generating an external shockwave and causing the shockwave to be incident upon (e.g. directing the shockwave towards) the input of the component.

[0056] Preferably the shockwave is arranged (allowed) to (at least initially) propagate along a direction parallel to the central (longitudinal) axis of the component. Thus, preferably the shockwave is arranged to be incident upon or is generated in the input of the component in a plane perpendicular to the central (longitudinal) axis of the component, e.g. parallel to a plane of the input of the component.

[0057] In embodiments, the matter to be compressed comprises a fuel, e.g. a fusionable fuel (e.g. hydrogen, deuterium and / or tritium) or a fuel-containing material, such that the method is a method of compressing fuel or a fuel-containing material,.

[0058] The invention also provides a system for compressing matter using an input shockwave and thus, from a further aspect, the invention provides a system for compressing matter using an input shockwave, the system comprising: a component according to any one of the aspects or embodiments described herein; and a mechanism for generating the input shockwave at the input of the component. It will 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. relating to other aspects and embodiments of the invention, as applicable.

[0059] In embodiments, the matter to be compressed comprises a fuel, e.g. a fusionable fuel (e.g. hydrogen, deuterium and / or tritium) or a fuel-containing material, such that the system is a system for compressing fuel or a fuel-containing material,.

[0060] In some embodiments, the mechanism comprises: a driving mechanism configured to drive a projectile into the component to generate a shockwave at the (e.g. input face of the) input of the component.

[0061] The projectile preferably comprises an impacting surface arranged to impact the (e.g. input of the) component.

[0062] In some embodiments, the impacting surface of the projectile comprises a substantially flat (e.g. planar) portion. Such projectiles may be used with a component having an input face comprising a concave portion. This may help to generate an input shockwave having a curved shock-front in the component.

[0063] In some embodiments, the impacting surface of the projectile comprises a curved (e.g. concave) portion. Such projectiles may be used with a component having an input face comprising a substantially flat portion. This may help to generate an input shockwave having a curved shock-front in the component.

[0064] The projectile may comprise any suitable and desired material. In some embodiments, the projectile has a shock-impedance greater than a shockimpedance of the second material (in the recess). In some embodiments, the projectile has a shock-impedance substantially equal to a shock-impedance of the body and / or the impedance matching layer. In some embodiments, the projectile has a shock impedance substantially equal to a shock-impedance of the second material (in the recess). In such embodiments, the projectile may comprise (e.g. is formed from, e.g. consists of) the second material. Preferably the projectile comprises (e.g. is formed from, e.g. consists of) a solid. Preferably the projectile comprises (e.g. is formed from, e.g. consists of) a high shock-impedance material. In embodiments the projectile comprises (e.g. is formed from, e.g. consists of) a metal, e.g. a refractory metal, e.g. tantalum. The projectile may comprise (e.g. be formed from, e.g. consists of) tungsten, steel, copper or other (e.g. heavy) metals. Thus, the projectile may be formed from the same material as the body and / or the impedance matching layer of the component.

[0065] In embodiments the projectile comprises (e.g. is formed from, e.g. consists of) a lower shock-impedance material, e.g. a low density metal, e.g. aluminium, or a lower density material, e.g. PMMA.

[0066] In some embodiments, the mechanism for generating a shockwave comprises an explosively driven mechanism, such as a gas gun, configured to drive the projectile into the component.

[0067] In some embodiments, the mechanism for generating a shockwave comprises an electromagnetic mechanism, such as a pulsed power machine magnetically driven plate flyer, configured to drive the projectile into the component.

[0068] In some embodiments, the (e.g. electromagnetic) mechanism for generating a shockwave comprises a direct drive mechanism configured to generate a Lorentz force in an electrode adjacent the component. In such embodiments, the Lorentz force generates a shockwave in the electrode which is transmitted to the input of the component.

[0069] In some embodiments, the mechanism for generating a shockwave comprises a laser drive mechanism. The mechanism may comprise an ablator layer adjacent the input of the component and one or more lasers configured to ablate the ablator layer creating a shockwave in the component. In embodiments, the lasers are incident directly on the ablator layer. In embodiments, the lasers are incident on a hohlraum surface, creating X-rays that bathe the ablator material causing it to ablate. It will be understood that where used herein, the term “shock-impedance” is intended to mean “'the pressure which must be applied to a medium in order to impart a unit particle velocity to some of the medium” (Henderson, ‘On the refraction of shock waves’, Journal of Fluid Mechanics, Volume 198, January 1989, pages 365-386). This is equal to the product of the shock speed and the density of the un-shocked material.

[0070] The component may have any suitable and desired dimensions, e.g. to be determined by the specific application of the component. In one embodiment the component has a thickness, diameter and / or maximum dimension 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. approximately 3 mm, 5 mm or 8 mm.

[0071] Certain embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0072] Figure 1a shows a cross sectional view of a component in accordance with embodiments of the invention;

[0073] Figure 1b shows a perspective view of the component of Figure 1a Figure 2 shows a system incorporating the component of Figure 1a;

[0074] Figure 3 shows a cross sectional view of a component in accordance with embodiments of the invention;

[0075] Figure 4 shows a cross sectional view of a component in accordance with embodiments of the invention;

[0076] Figure 5 shows a cross sectional view of a component in accordance with embodiments of the invention;

[0077] Figures 6 and 7 show cross sectional views of components which are variants of the component of Figure 1a; and

[0078] Figures 8 to 13 show cross sectional views of components which are variants of the component of Figure 3.

[0079] Components and systems for compressing matter (e.g. fuel) by producing high localised concentrations of energy by manipulating an input shockwave to produce a high pressure quasi-spherical shockwave incident on the matter to be compressed will now be described. It will be understood that where used herein, the terms “top”, “bottom”, “up”, “down”, “side”, “base”, etc., are included for clarity and are intended to refer to the orientation shown in the enclosed Figures. It will be appreciated that, in use, the components and systems may operate in any suitable and desired orientation.

[0080] Figures 1a and 1b show cross-sectional and perspective views respectively of a component 1 in accordance with an embodiment of the invention.

[0081] The illustrated cross-section is taken in a plane containing a central longitudinal axis Z of the component 1. In the illustrated embodiment, the component 1 is rotationally symmetrical about the central axis Z, as can be seen from Figure 1b.

[0082] The component 1 comprises three portions: a body 2, a focussing element 9 and a target volume 12. The body 2 defines a bowl-shaped recess 4. The recess 4 is defined by recess walls 6, the angle of which varies continuously (e.g. is curved) such that the recess 4 is bowl-shaped.

[0083] The top face of the component forms an input 10 that is configured to receive an input shockwave. The body 2 is formed of a material having a high shockimpedance. In an exemplary embodiment, the body 2 is formed of tantalum. The body 2 may be formed of other materials, for example other heavy metals, e.g. tungsten, steel, copper or platinum.

[0084] The recess 4 is filled with a solid material 8 having a low shock-impedance material, such as PMMA or epoxy resin. A focussing element 9 is embedded within the material 8, as can be seen from Figures 1a and 1b. In the illustrated embodiment, the focussing element 9 is formed of gold, but the focussing element may be formed of other materials, e.g. other metals such as aluminium or copper.

[0085] For illustrative purposes, the recess fill material 8 has been omitted from Figure 1b such that the top of the target element can be seen. The focussing element 9 is ovoidal (i.e. egg shaped) and defines a target volume 12 configured to contain the matter to be compressed. The focussing element 9 is fully surrounded by the material 8 filling the recess 4, such that the focussing element 9 is spaced from the recess walls 6. Operation of the component 1 , will now be explained with reference to Figures 1a, 1 b and 2. Figure 2 shows a system in accordance with an embodiment of the invention, incorporating the component 1 of Figures 1a and 1b.

[0086] The input 10 is configured to receive a shockwave. In the embodiment shown in Figure 2, this shockwave is generated by striking the input 10 of the component 1 with a disc shaped projectile 13 having a flat impacting surface 14. In the illustrated embodiment, the projectile 13 is at least partially formed of tantalum, but may be formed of other heavy metals such as tungsten, platinum, steel, or copper.

[0087] The shockwave that is generated at the input 10 propagates through the recess fill material 8 and is reflected from the recess walls 6 as a result of the significant shock-impedance difference at the boundary between the low shock-impedance recess fill material and the high shock-impedance body 2. Owing to the curved shape of the recess walls, shockwave elements are reflected towards the focussing element 9. These reflections (in combination with the original propagating shockwave) result in a partially spherical shockwave being incident on the focussing element 9.

[0088] As the shockwave propagates through the focussing element 9, it is further spherically focussed by the shape of the focussing element, resulting in a spherical shock state at the location of the target volume 12. This shock state acts to compress and thus compress the matter in the target volume 12.

[0089] In the embodiment of Figures 1a and 1b, the focussing element is ovoidal (i.e. egg shaped) and defines a spherical target volume 12 that is configured to contain the matter to be compressed. In the illustrated embodiment, the target volume 12 is centred on the central longitudinal axis Z.

[0090] The target volume 12 is not concentric with the focussing element 9. Rather the centre of the target volume 12 is lower (i.e. further from the input 10) than the centre of the focussing element. This offset acts to spherically focus the shock because the portion of the shock-front which is propagating along the longitudinal axis Z has more material to travel through before reaching the target volume 12 than the portions of the shock front which have been reflected from the recess walls 6 and which are approaching the target volume 12 from the side. This gives the portions of the shock-front to the side of, and below, the target volume 12 chance to catch-up and wrap around such that the entire shock front reaches the target volume 12 together.

[0091] Figure 3 shows a cross-sectional view of a component 40 which is a variant of the component 1. The illustrated cross-section is taken in a plane containing a central longitudinal axis Z of the component 40.

[0092] The component 40 comprises a similar body 42 and recess fill material 48 to the component 1 of Figures 1a, 1b and, and is configured to function in a similar way as described in relation this embodiment, by receiving an input shockwave, such as via an impacting projectile, at the input 410.

[0093] However, the focussing element 49 of the component 40 shown in Figure 3 differs from the focussing element 9 of the component 1 shown in Figures 1a, 1b and 2. The focussing element 49 of component 40 comprises a plurality of shells (e.g. encompassing layers) formed of different materials having different shockimpedances.

[0094] In the embodiment of Figure 3, the shock-impedance of the shells increases progressively from the outer surface 43 of the focussing element to the target volume 412. In the specific example shown in Figure 3, the body 42 is formed from tantalum, the recess fill material 48 is formed from PMMA, and the focussing element 49 comprises a first shell 421 that defines the outer surface 43 of the focussing element 49 and is formed from aluminium, a second (middle) shell 422 formed from copper, and a third shell 423 formed from gold, which defines the target volume 412. It will be understood that these specific materials are simply exemplary, and that other suitable materials could be used to form the plurality of shells.

[0095] In use, the initial projectile impact sets up a strong shockwave that travels faster in the first shell 421 than in the second shell 422, and faster in the second shell 422 than in the third shell 423. Hence, by controlling the ratios of the shock impedance and distance travelled in each shell, it is possible to manipulate the shockwave as it propagates through the focussing element 49 such that the portions of the shockwave propagating towards the target volume 412 from different angles arrive at the target volume 412 simultaneously and act together to compress the matter to be compressed in a spherical implosion.

[0096] The large impedance mismatch between the recess fill material 48 and the first shell 421 acts to keep a large amount of the energy trapped inside the focussing element because it is difficult for shock portions that are reflected from the boundary between the first shell 421 and the second shell 422 to propagate across the boundary from the first shell 421 back into the recess fill material 48. It is far more likely that these shock portions would be reflected back from the boundary between the first shell 421 and the recess fill material 48, back towards the target volume 412.

[0097] Meanwhile, the incremental shock-impedance changes between the first shell 421, the second shell 422 and the third shell 423 help to increase the coupling between the shells, reducing the degree of reflection from the shell boundaries.

[0098] Each of the shells 421 , 422, 423 is ovoidal and the shells 421, 422, 423 and the target volume 412, are not concentric. Rather, moving from the input 410 towards the target volume 412, the centre of each shell is further from the input 410 than the centre of the previous shell.

[0099] The result of this is that the shells 421 , 422, 423 are thickest at the longitudinal axis Z. This acts to further spherically focus the shockwave because the portion of the shock-front that is propagating along the longitudinal axis has more material to travel through before reaching the target volume 412. This gives the portions of the shock-front to the side of, and below, the target volume 412 chance to catch-up and wrap around such that the entire shock front reaches the target volume 412 together.

[0100] Also envisaged is a variant of Figure 3 wherein the focussing element is not formed as discrete shells, but rather is unitarily formed as a structure that has a continuously varying shock-impedance. The function of such a focussing element is substantially the same as the focussing element 49, but the lack of discrete layers reduces issues associated with coupling between shells since there are no discrete shell boundaries to reflect shockwaves away from the target volume. Such a continuous focussing element may be formed using two-photon polymerisation to 3D print the focussing element as a variable density foam.

[0101] Figure 4 shows a cross section through a component 60 that is a variant of the component 1 shown in Figures 1a, 1b and 2. The component 60 shown in Figure 4 is similar to the component 1 shown in Figures 1a, 1b and 2, other than an additional element, which takes the form of an inverted hollow cone 61 , on top of the focussing element 69, between the focussing element 69 and the input 610.

[0102] The base of the cone rests on the focussing element 69, while the apex of the cone is adjacent the input 610 of the component 60. The cone 61 is formed of a high density material, for example tantalum. The cone 61 has the effect of focussing the shockwave in the recess fill material 68 fill towards the recess walls 66 (via reflections from the sides of the cone 61). This results in shock portions reaching the underside of the focussing element 69 more quickly.

[0103] Furthermore, since the high-density cone 61 is blocking the direct route from the input to the focussing element 69, the shock portions propagating parallel to the Z axis are slowed. The combination of these effects is an more uniform shock state at the location of the target volume 612 since the shock portions approaching the target volume 612 from the underside are given a chance to catch up with those shock portions which re approaching the target volume directly from the input 610.

[0104] Although the cone 61 has been illustrated as a modification to the component 1 of Figures 1a, 1b and 2, it will be understood that the cone 61 may be incorporated into any of the rotationally symmetric components described herein.

[0105] Figure 5 shows a cross sectional view through a component 70 that is a variant of the component 1 shown in Figures 1a, 1b and 2. The component 70 shown in Figure 5 comprises a similar body 72 and recess fill material 78 to the component 1 shown in Figures 1a, 1b and 2, but the component 70 shown in Figure 5 comprises a focussing element 79 that comprises a plurality of ovoidal shells 717, 719. The shells 717, 719 of the focussing element 79 of the component 70 shown in Figure 5 differ from the shells of the focussing elements 49, 59 of the components 40, 50 shown in Figures 4 and 5, in that the shells of the focussing element 79 of the component 70 shown in Figure 5 do not have shock-impedances that vary progressively. Instead, the focussing element 79 comprises a plurality of high shock-impedance shells 717 and a plurality of low shock-impedance shells 719.

[0106] The shells 717, 718 are arranged to alternate between high shock-impedance shells 717 and low shock-impedance shells 719. As can be seen from Figure 5, the high shock-impedance shells 717 are thinner than the low shock-impedance shells 719. The shells 717, 719 are arranged such that shockwaves propagating through the focussing element 79 reverberate within the shells, as a result of reflections from the boundaries between low and high shock-impedance shells 717, 719, leading to portions of constructive and destructive interference as shock waves pass over one another. When a shock passes from a low shock-impedance shell 719 into a high shock-impedance shell 717 a portion of the shock is transmitted into the high shock-impedance layer 717 whilst a portion is reflected back into the low shock-impedance layer 719.

[0107] The portion in the low shock-impedance layer 719 speeds up since it is now travelling through pre-shocked material. The shock portion then reflects from the boundary between the shells, and since it has been sped up, the reflected portion eventually catches up with the portion of the shock that was initially transmitted into the high shock-impedance shell 717.

[0108] Through the arrangement of the low and high shock-impedance shells 717, 719, the focussing element 79 can be arranged such that a plurality of shock portions superimpose at the target volume 712, leading to a short-lived high shock pressure state that may be sufficient to collapse fusionable fuel which is contained within the target volume 712.

[0109] As in the other embodiments, described herein, in the embodiment of Figure 5, the target volume 712 is not concentric with the focussing element 79. Rather the centre of the target volume 712 is lower (i.e. further from the input 710) than the centre of the focussing element 79.

[0110] In the illustrated embodiment, all of the high shock-impedance shells 717 are formed from the same material, and all of the low shock-impedance shells 719 are formed from the same material. In some embodiments, different low shockimpedance materials may be used for the different low shock-impedance shells 719 and different high shock-impedance materials may be used for the different high shock-impedance shells 717.

[0111] It will be understood that the alternating high to low shock-impedance shell configuration shown in Figure 5 is not limited to being a variant of the component 1 of Figures 1a, 1b and 2. For example, the component geometry shown in Figures 6 to 11 may also be modified to comprise a plurality of alternating shock-impedance shells as described above, and it will be understood that the principle of superposition as a result of reflections between shell boundaries will be similar for such a component.

[0112] A potential issue with components of the present invention, is the formation of a high pressure jet at the “south pole” of the component (i.e. below the focussing element). The jetting is caused by the portions of the shock travelling from different directions (e.g. along the recess walls) overlapping.

[0113] Figures 6 and 7 show variants of the component of claim 1 which are designed to mitigate this jetting effect.

[0114] The component of Figure 6 comprises a shaped impedance matched layer 80 which is placed between the focusing element and recess wall at the south pole. This layer 80 acts to slow the formation of any jet. In the illustrated embodiment, the shaped impedance matched layer 80 is formed of a material having a having a high shock-impedance such as tantalum, tungsten, platinum, steel, or copper. In other embodiments however, the shaped impedance matched layer 80 may be formed of low shock-impedance material, such as PMMA or epoxy resin. The component of Figure 7 has a recess wall which is shaped to provide a depression 81 at the south pole. This depression results in a reduction of pressure upon shock overlap which may reduce the effect of jetting.

[0115] Figures 8 to 13 show components which represent variants of the component which is shown in Figure 5, and discussed in detail above. Like the component 70 of Figure 5, the components 90 of Figures 8 to 13 each comprise a body 92 defining a recess 94 filled with recess fill material 98. Further, like the focussing element 79 of component 70 the focussing elements 99 of components 90 comprise a plurality of high shock-impedance shells 917 and a plurality of low shock-impedance shells 919.

[0116] The shells 917, 919 are arranged to alternate between high shock-impedance shells 917 and low shock-impedance shells 919. The shells 917, 919 are arranged such that shockwaves propagating through the focussing element 99 reverberate within the shells, as a result of reflections from the boundaries between low and high shock-impedance shells 917, 919, leading to portions of constructive and destructive interference as shock waves pass over one another. When a shock passes from a low shock-impedance shell 919 into a high shock-impedance shell 917 a portion of the shock is transmitted into the high shock-impedance layer 917 whilst a portion is reflected back into the low shock-impedance layer 919.

[0117] The portion in the low shock-impedance layer 919 speeds up since it is now travelling through pre-shocked material. The shock portion then reflects from the boundary between the shells, and since it has been sped up, the reflected portion eventually catches up with the portion of the shock that was initially transmitted into the high shock-impedance shell 917.

[0118] Through the arrangement of the low and high shock-impedance shells 917, 919, the focussing element 99 can be arranged such that a plurality of shock portions superimpose at the target volume 912, leading to a short-lived high shock pressure state that may be sufficient to compress matter (e.g. collapse fusionable fuel) which is contained within the target volume 912. As in the other embodiments described herein, in each of the components 90 shown in Figures 8 to 13 the target volume 912 is not concentric with the layers of the focussing element 99. Rather the centre of the target volume 912 is lower (i.e. further from the input 910) than the centres of the focussing element layers.

[0119] In the illustrated embodiments, all of the high shock-impedance shells 917 are formed from the same material, and all of the low shock-impedance shells 919 are formed from the same material. In some embodiments, different low shockimpedance materials may be used for the different low shock-impedance shells 919 and different high shock-impedance materials may be used for the different high shock-impedance shells 917.

[0120] Most significantly, the geometries of the components 90 differ from the component 70 in that the input 910 is not the widest point of the recess 94. Rather, each of the recesses 94 are approximately bowl-shaped with walls which curve back towards the central axis of the recess towards the input 910, in a similar manner to that of a balloon glass. Further, it can be seen that the recesses 94 of the embodiments of Figures 8, 9, 11, and 13 all comprise an inflection (towards the target volume 412) at their bases.

[0121] The focussing elements 99, and by extension the layers 917, 919 of the focussing elements 99, each have approximately ovoidal shapes, but, in contrast to the focussing element 79 of Figure 5, the more tapered end of the ovoids is proximal to the base of the recesses 94 and the more rounded end of the ovoids is proximal to the input 910 of the recess. In embodiments where an inflection is present at the base of the recess, this inflection is also present in the base of the focussing element 99. This is most prominent in the component 90 of Figure 9.

[0122] It will be understood that the specific shapes shown in Figures 8 to 13 are exemplary, and other suitable configurations and designs are envisaged.

[0123] Although specific examples have been given, it will be appreciated that there are a large number of parameters that may influence the actual results achieved. In the embodiments described above, some of the diagrams shown are a vertical cross-section through a three-dimensional component and hence they depict embodiments that are rotationally symmetric. However, this is not essential to the invention.

[0124] It will be understood that the embodiments explicitly disclosed herein are intended to be exemplary, and the skilled person will understand that features of the embodiments disclosed herein may, except where mutually exclusive, be combined in combinations not explicitly mentioned in order to form new embodiments.

[0125] Although the input faces of the components shown in the illustrated embodiments are planar, it will be appreciated that embodiments exist in which the input face of the component is at least partially non-planar, e.g. curved, e.g. convex or concave. Similarly, although the projectiles shown in the illustrated embodiments are planar, it will be appreciated that embodiments exist in which the (e.g. impact face of the) projectile is at least partially non-planar, e.g. curved, e.g. convex or concave.

[0126] Embodiments of the invention may be suitable for amplifying shockwaves for the purpose of generating conditions suitable for nuclear fusion; however, the invention is not limited to this, and may be used for other applications.

Claims

Claims1. A component for compressing matter using an input shockwave, the component comprising: a body comprising a recess wall defining a recess; an input for inputting the input shockwave into the component; and a focussing element within the recess; wherein the focussing element defines a volume configured to contain the matter to be compressed; wherein the recess wall is configured to reflect the input shockwave towards the focussing element; and wherein the focussing element is configured to focus the reflected shockwave onto the volume.

2. The component as claimed in claim 1 , wherein the body comprises a first material; wherein the recess contains a second material; and wherein the second material has a lower shock-impedance than the shockimpedance of the first material.

3. The component as claimed in claim 1 or 2, wherein the input of the component is provided by an outer surface of the body and / or an outer surface of the second material of the recess.

4. The component as claimed in claim 1 , 2 or 3, wherein the recess wall comprises a curved portion.

5. The component as claimed in any one of the preceding claims, wherein the recess is bowl-shaped, e.g. substantially hemispherical.

6. The component as claimed in any one of the preceding claims, wherein the body comprises a first material; wherein the recess contains a second material; and wherein the focussing element is contained within the second material.

7. The component as claimed in any one of the preceding claims, wherein the body comprises a first material; wherein the recess contains a second material; and wherein the second material and the focussing element are contiguous.

8. The component as claimed in any one of the preceding claims, wherein the body comprises a surface defining the recess; and wherein the focussing element is spaced from the surface defining the recess.

9. The component as claimed in any one of the preceding claims, wherein the focussing element is substantially ovoidal.

10. The component as claimed in any one of the preceding claims, wherein the focussing element has a shock impedance that varies through the focussing element.

11. The component as claimed in any one of the preceding claims, wherein the shock-impedance proximal to an outer surface of the focussing element is lower than the shock-impedance proximal to the volume.

12. The component as claimed in any one of the preceding claims, wherein the focussing element comprises a plurality of shells.

13. The component as claimed in claim 12, wherein two or more of the plurality of shells have a shock-impedance that is different from each other.

14. The component as claimed in claim 13, wherein the shock-impedance of the shells of the two or more shells increases progressively from an outer surface of the focussing element towards the volume.

15. The component as claimed in claim 12, wherein the plurality of shells comprises one or more first shells comprising a third material having a third shock-impedance, and one or more second shells comprising a fourth material having a shock-impedance that is lower than a shock-impedance of the third material.

16. The component as claimed in claim 15, wherein the plurality of shells comprises a plurality of first shells and / or a plurality of second shells, wherein the plurality of shells alternate between the first shells and the second shells.

17. The component as claimed in any one of claims 1 to 11 , wherein the focussing element is formed unitarily and has a shock-impedance that varies progressively from an outer surface of the focussing element towards the volume.

18. A method of compressing matter using an input shockwave, the method comprising generating the input shockwave at the input of the component according to any one of the preceding claims.

19. A system for compressing matter using an input shockwave comprising: a component as claimed in any one of claims 1 to 17; and a mechanism for generating the input shockwave at the input of the component.

20. The system as claimed in claim 19, wherein the mechanism comprises: a driving mechanism configured to drive a projectile into the component to generate a shockwave at the input of the component.

21. The component as claimed in any of claims 1 to 17, or the method as claimed in claim 18, or the system as claimed in claim 19 or claim 20, wherein the matter to be compressed comprises a fuel.

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