Apparatus and method for magnetic field compression using a toroid coil structure

An apparatus for magnetic field compression includes a toroid and a plurality of separate coils wound around the toroid. The coils are spaced about a circumference of the toroid and each coil generates a magnetic field in response to electric current flowing in the coil. The toroid and a group of the coils each include a size that respectively gradually decreases over a predetermined portion of the toroid. The magnetic field is compressed or has a highest magnetic flux density proximate a central region of the coils around the toroid.

CROSS REFERENCE TO RELATED APPLICATION

This application is related to U.S. application Ser. No. 15/784,831, entitled “Apparatus and Method for Magnetic Field Compression,” which is assigned to the same assignee as the present application, filed on the same date as the present application, and is incorporated herein by reference.

This application is related to U.S. application Ser. No. 15/785,022, entitled “Apparatus and Method for Generating a High Power Energy Beam Based Laser,” which is assigned to the same assignee as the present application, filed on the same date as the present application, and is incorporated herein by reference.

FIELD

The present disclosure relates to devices and methods for generating magnetic fields and more particularly to an apparatus and method for magnetic field compression using a toroid coil structure.

BACKGROUND

Permanent magnetics generate a maximum magnetic field strength or maximum magnetic flux of about one (1) Tesla (T). Magnetic materials that may be used to enhance magnetic field strength or magnetic flux saturate at about 1 T. Substantially higher magnetic field strengths of about 10 T or higher may be achieved in small limited volumes but generally require large coils wound with wire or tape of a superconducting material. Accordingly, there is a need for an apparatus and method for generating large-scale or high strength magnetic fields for certain applications, such as for example, controlling high-energy electron or ion beams or similar radiation beams.

SUMMARY

In accordance with an embodiment, an apparatus for magnetic field compression includes a toroid and a plurality of separate coils wound around the toroid. The coils are spaced about a circumference of the toroid and each coil generates a magnetic field in response to electric current flowing in the coil. The toroid and a group of the coils each include a size that respectively gradually decreases over a predetermined portion of the toroid. The magnetic field is compressed or has a highest magnetic flux density proximate a central region of the coils around the toroid.

In accordance with another embodiment, an apparatus for magnetic field compression includes a first toroid and a first plurality of separate coils wound around the first toroid. The coils being spaced about a circumference of the toroid and each coil generating a magnetic field in response to electric current flowing in the coil. The apparatus also includes a second toroid and a second plurality of separate coils wound around the second toroid. The coils being spaced about a circumference of the second toroid and each coil generating a magnetic field in response to electric current flowing in the coil. A center opening of the first toroid and a center opening of the second toroid are in a same plane and the second toroid is disposed adjacent the first toroid at a predetermined distance from the first toroid. The apparatus further including an aperture defined between two adjacent coils of the first plurality of separate coils and two adjacent coils of the second plurality of separate coils. The magnetic field is compressed within the aperture in response to electric current flowing in the coils of the first plurality of separate coils and the second plurality of separate coils. The predetermined distance or aperture is sized for placing an object in the aperture or the aperture is configured for controlling an electron beam based laser.

In accordance with a further embodiment, a method for magnetic field compression includes providing a toroid and winding a plurality of separate coils around the toroid. The coils are spaced about a circumference of the toroid and each coil generates a magnetic field in response to electric current flowing in the coil. The toroid and a group of the coils each include a size that respectively gradually decreases over a predetermined portion of the toroid. The magnetic field is compressed or has a highest magnetic flux density proximate a central region of the coils around the toroid.

In accordance with another embodiment or any of the previous embodiments, the toroid and each of the coils around the toroid include opposite rounded ends connected by elongated sides.

In accordance with another embodiment or any of the previous embodiments, wherein the predetermined portion includes about half a circumference of the toroid from a pair of points each about half the circumference on the toroid apart.

In accordance with another embodiment or any of the previous embodiments, wherein each of the coils include a superconducting material.

In accordance with another embodiment or any of the previous embodiments, wherein the coils are enveloped in a diamagnetic material or a magnetic material that mimics a behavior of the magnetic flux density for the coils including a superconducting material.

In accordance with another embodiment or any of the previous embodiments, wherein the apparatus further includes an electric current supply electrically connected to each coil.

In accordance with another embodiment or any of the previous embodiments, wherein each electric current supply includes an adjustable current supply configured for adjusting a balance of currents between the coils.

In accordance with another embodiment or any of the previous embodiments, wherein the apparatus further includes a single electric current supply for supplying electrical current to each of the coils.

In accordance with another embodiment or any of the previous embodiments, wherein the coils include a predetermined size for inserting an object within the coils.

In accordance with another embodiment or any of the previous embodiments, wherein the coils are configured to control an electron beam based laser.

In accordance with another embodiment or any of the previous embodiments, wherein the toroid includes an electrical insulation material.

In accordance with another embodiment or any of the previous embodiments, wherein the separate coils are uniformly spaced about the circumference of the toroid.

In accordance with another embodiment or any of the previous embodiments, wherein the toroid defines a first toroid and the plurality of separate coils defines a first plurality of separate coils. The apparatus further includes a second toroid and a second plurality of separate coils wound around the second toroid. The coils are spaced about a circumference of the second toroid and each coil generates a magnetic field in response to electric current flowing in the coil. A center opening of the first toroid and the second toroid are in a same plane and the second toroid is disposed adjacent the first toroid at a predetermined distance from the first toroid. An aperture is defined between two adjacent coils of the first plurality of separate coils and two adjacent coils of the second plurality of separate coils. The magnetic field is compressed within the aperture in response to electric current flowing in the coils of the first plurality of separate coils and the second plurality of separate coils. The predetermined distance or aperture is sized for placing an object in the aperture or the aperture is configured to control an electron beam based laser.

DETAILED DESCRIPTION

The following detailed description of embodiments refers to the accompanying drawings, which illustrate specific embodiments of the disclosure. Other embodiments having different structures and operations do not depart from the scope of the present disclosure Like reference numerals may refer to the same element or component in the different drawings.

FIG. 1is a perspective view of an example of an apparatus100including a toroid coil structure102. At a given height and radius, the magnetic field does not change in the circumferential direction, i.e., there is no magnetic flux compression. The apparatus100serves as a reference for the embodiments described herein that produce magnetic flux compression.FIG. 2is a cross-sectional view of the exemplary apparatus100inFIG. 1taken along lines2-2. A radius of the toroid104is represented by the arrow “R.” The apparatus100or toroid coil structure102includes a toroid104and a plurality of separate coils106wound around the toroid104. The toroid104is formed from an electrical insulator material105. An example of the electrical insulator material105includes but is not necessarily limited to a G10 material or other composite material suitable for cryogenic applications. In accordance with other embodiments, the toroid coil structure102includes a geometric shape other than a circular shape or doughnut shape in a plan view of the toroid coil structure102. In accordance with an example, the toroid coil structure102include an elliptical shape, ellipsoid shape or is oblong in one direction. Other geometric shapes are applicable depending upon the application and/or desired distribution of the magnetic field or fields associated with the toroid coil structure102.

In accordance with the embodiment illustrated inFIG. 1, the coils106are uniformly spaced about a circumference of the toroid104. In another embodiment, the coils106are non-uniformly spaced or are spaced according to a preset pattern to provide a particular magnetic field distribution within the toroid104. The coils106include electrically conductive material or semiconductor material. In accordance with an embodiment, the coils106are formed from or include a superconducting material108(FIG. 2). Examples of the superconducting material108include a ceramic material disposed on a substrate110(FIG. 2). The substrate110is typically a metallic material. Other examples of the superconducting material108include but are not necessarily limited to a superconducting crystalline material grown on a surface of the substrate110. The superconducting ceramic material is plated on the substrate110, plasma sprayed on the substrate110, or thermal-sprayed on the substrate110. The substrate110includes any suitable material for growing the superconducting crystalline material or any suitable mechanical frame for the superconducting ceramic material. For example, the substrate110includes one of steel, a nickel alloy, carbon fiber composite or other suitable frame material for the superconducting material108. In accordance with other examples, the superconductors are formed by metalorganic chemical vapor deposition (MOCVD), ion beam assisted deposition (IBAD) or similar superconductor fabrication techniques. Other examples of the superconducting material108include a superconducting alloys.

Each coil106generates a magnetic field112in response to electric current114flowing in the coil106. The electric current includes one of continuous electric current, alternating electric current or pulsed electric current. In accordance with an embodiment, an electric current supply116is electrically connected to each coil106. In another embodiment, a single electric current supply is configured to individual feed each coil106. The electric current supply116or electric current supplies are configured to supply one of continuous electric current, alternating electric current or pulsed electric current. InFIG. 2, the magnetic field112has a highest magnetic flux density in a region proximate an inner part of the windings118of the coils106around a circumference of the toroid104. In accordance with an embodiment, an aperture120is defined within the coils106for inserting an object122(FIG. 2). The coils106include a predetermined size for inserting the object122within the coils106. In accordance with another embodiment described with reference toFIG. 4, an aperture120is defined between two coils106or406(FIG. 4) for inserting an object122. In accordance with a further embodiment described with reference toFIG. 6, an aperture120is defined between two adjacent toroids for inserting an object122.

In one example, the apparatus100is part of a magnetic resonance image machine (not shown) for performing magnetic resonance imaging of the object122. The apparatus100is applicable to non-destructive evaluation and imaging techniques, such as magnetic resonance imaging for medical purposes or other imaging applications. In another example described in U.S. application Ser. No. 15/785,022, entitled “Apparatus and Method for Generating a High Power Energy Beam Based Laser,” the object122is an electron beam, ion beam or the like that is controlled by the apparatus100. Accordingly, the coils106and/or aperture120are configured to control an electron beam, electron beam based laser, ion beam or the like. The apparatus100is applicable for any purpose where a high magnetic field strength or high magnetic flux up to about 10 T or higher in the aperture120is desired.

In accordance with an example, the electric current supply116or electric current supplies are an adjustable electric current supply or supplies configured for adjusting an amplitude and/or frequency of electric current applied to each of the coils106. The adjustable current supply or supplies are used for balancing the electric currents between the coils106or for supplying the electric currents to the coils106in a certain scheme or configuration to provide a predetermined magnetic field distribution or predetermined magnetic flux density by the coils106.

In accordance with the embodiment illustrated inFIGS. 1 and 2, the toroid104and each of the coils106around the toroid104include opposite rounded ends124connected by opposite elongated sides126as best shown inFIG. 2. Each of the coils106include a uniform radial width (“W”) and a length (“L”). In other embodiments, the toroid104and coils106define different geometric shapes depending upon the application and/or magnetic field distribution desired. For example, the cross-section of the toroid coil structure may be circular, elliptical, square or some other geometric shape. In accordance with an embodiment described with reference toFIG. 3, a group of coils106include a size that respectively gradually decreases over a predetermined portion of the toroid104. A cross-section of the toroid104gradually decreases over the predetermined portion corresponding to the gradually decreasing size of the coils106.

FIG. 3is a perspective view of an example of an apparatus300for magnetic field compression using a toroid coil structure302in accordance with another embodiment of the present disclosure. The apparatus300or toroid coil structure302includes a toroid304and a plurality of separate coils306. The toroid304includes an electrical insulator material105(FIG. 2). In accordance with an embodiment, the coils306include electrically conductive material or semiconductor material. In accordance with another embodiment, the coils306are formed from or include a superconducting material. In accordance with the example shown inFIG. 3, the coils306are uniformly spaced about a circumference of the toroid304. In other embodiments, the coils306are non-uniformly spaced or are spaced according to a preset pattern to provide a particular magnetic field distribution within the toroid304. The apparatus300is similar to the apparatus100inFIGS. 1 and 2except a group308of the coils306include a size that respectively gradually decreases over a predetermined portion310of the toroid304. A cross-section of the toroid304gradually decreases in size over the predetermined portion310of the toroid304in correspondence with the respective gradual decrease in size of the coils306over the predetermined portion310. Accordingly, the width (“W”) and length (“L”) of the coils306and cross-section of the toroid304gradual decrease over the predetermined portion310. In accordance with an example, the coils306include radial widths312that respectively gradually decrease over about half a circumference of the toroid304from a pair of points314and316each about half the circumference on the toroid304apart. The magnetic field112is compressed or has a highest magnetic flux density proximate a central region118of the coils306around the toroid304. In accordance with an embodiment, an aperture318may be defined between any two coils306or between the two smallest coils306for inserting an object, such as object122(FIG. 2). The magnetic field112is compressed or has a highest magnetic flux density within the aperture318between the two smallest coils306. In accordance with an embodiment, each of the coils306has a structure the same as or similar to the coil106described with reference toFIG. 2

FIG. 4is a perspective view of an example of an apparatus400for magnetic field compression using a toroid coil structure402in accordance with a further embodiment of the present disclosure.FIG. 5is a cross-sectional view of the exemplary apparatus400for magnetic field compression inFIG. 4taken along lines5-5. The toroid coil structure402includes a toroid404and a plurality of coils406wound around the toroid404. In accordance with an embodiment, the toroid coil structure402is similar to the toroid coil structure102inFIGS. 1 and 2. In accordance with another embodiment, the toroid coil structure402is similar to the toroid coil structure302inFIG. 3. The apparatus400is similar to the apparatus100inFIG. 1or the apparatus300inFIG. 3except apparatus400includes a magnetic material or a diamagnetic material408that envelopes the outside of the coils406and bridges a space between the coils406. In accordance with an embodiment, the diamagnetic material408includes a relative permeability (magnetic permeability divided by the magnetic permeability of free space) of about 0.001. The diamagnetic material408mimics a behavior of the magnetic flux density for the coils406including a superconducting material inFIG. 5. In accordance with an embodiment, the diamagnetic material408includes an aperture410(FIG. 4) in which the magnetic field112is compressed. Similar to that previously described, the magnetic field112is compressed or has a highest magnetic flux density proximate a center or central region412(FIG. 5) of the coils406around a circumference of the toroid404. The apparatus400and aperture410are sized for inserting an object, such as object122, within the aperture410for performing an operation or function with respect to the object122using the compressed magnetic field112in the aperture410similar to that previously described.

FIG. 6is a perspective view of an example of an apparatus600for magnetic field compression using a pair of toroid coil structures302aand302bin accordance with another embodiment of the present disclosure. The apparatus600is similar to the apparatus 700 in FIGS. 7A and 7B in U.S. application Ser. No. 15/785,022, entitled “Apparatus and Method for Generating a High Power Energy Beam Based Laser.” In accordance with the exemplary embodiment shown inFIG. 6, each toroid coil structures302aand302bis similar to the toroid coil structure302inFIG. 3. In accordance with another embodiment each toroid coil structure302aand302bis similar to the toroid coil structure102inFIG. 1. The apparatus600includes a first toroid coil structure302aand a second toroid structure302b. The first toroid coil structure302aincludes a first toroid304a. The second toroid coil structure302bincludes a second toroid304b. The first toroid304aand the second toroid304binclude or are formed from an electrical insulator material. An example of the electrical insulator material includes but is not necessarily limited to a G10 material or other composite material suitable for cryogenic applications.

A first plurality of separate coils306aare wound around the first toroid304a. The first plurality of coils306aare placed about a circumference of the first toroid304aand each coil306agenerates a first magnetic field320ain response to electric current114(FIG. 5) flowing in the coils306a. A second plurality of separate coils306bare wound around the second toroid304b. The second plurality of coils306bare placed about a circumference of the second toroid304band each coil306bgenerates a second magnetic field320bin response to electric current114flowing in the coils306b. Each coil306aand306bincludes electrically conductive material or semiconductor material. In accordance with an embodiment, the coils306aand306bare formed from or include a superconducting material108similar to that previously described.

A circular center opening322aof the first toroid coil structure302aand a circular center opening322bof the second toroid coil structure302bare in a same plane and the second toroid coil structure302bis disposed adjacent the first toroid coil structure302aat a predetermined distance (“D”) from the first toroid coil structure302a. An aperture324is defined between two adjacent coils of the first plurality of separate coils306aand two adjacent coils of the second plurality of separate coils306b. The magnetic fields320aand320bare compressed within the aperture324in response to electric current flowing in the coils of the first plurality of separate coils306aand the second plurality of separate coils306b. The predetermined distance D or aperture324is sized for placing an object326in the aperture324. In accordance with an embodiment, the aperture324is configured for controlling an electron beam based laser similar to that described in U.S. application Ser. No. 15/785,022, entitled “Apparatus and Method for Generating a High Power Energy Beam Based Laser.”

In accordance with the embodiment illustrated inFIG. 6, the first plurality of coils306aare uniformly spaced about the circumference of the first toroid304aand the second plurality of coils306bare uniformly spaced about the circumference of the second toroid304b. In another embodiment, the first plurality of coils306aand/or the second plurality of coils306bare non-uniformly spaced or are spaced according to a preset pattern to provide a particular magnetic field distribution within the first toroid coil structure302aand/or the second toroid coil structure302b.

In accordance with an embodiment, the toroid coil structures302aand302bare encased or enclosed in a magnetic or diamagnetic material similar to diamagnetic material408inFIG. 4. In accordance with an example, a piece material328including a predetermined relative permeability is inserted into the aperture324or a portion of the aperture324to control or adjust the compression or strength of the magnetic fields320aand320bwithin the aperture324. In accordance with a further embodiment the relative permeability is less than 1.0. For example, the aperture324includes an air gap (relative permeability of 1.0) or a piece of material328with a relative permeability less than 1.0 is inserted into the aperture324or portion of the aperture324to control or adjust the compression or strength of the magnetic fields320aand320bwithin the aperture324.

FIG. 7is a flow chart of an example of a method700for magnetic field compression in accordance with an embodiment of the present disclosure. The method700may be embodied in and performed by the apparatus100inFIGS. 1 and 2, apparatus300inFIG. 3, apparatus400inFIGS. 4 and 5or apparatus600inFIG. 6. In block702, a toroid coil structure is provided. In accordance with an embodiment, block702includes blocks704and706. In block702, a toroid is provided. In block706, a plurality of separate coils are wound around the toroid. The coils are spaced about a circumference of the toroid and each coil generates a magnetic field in response to electric current flowing in the coil. The coils are uniformly spaced or non-uniformly spaced. The magnetic field is compressed or has a highest magnetic flux density proximate a central region of the coils around the toroid. In accordance with an embodiment, a size of the coils gradually decreases over a predetermined portion of the toroid. A cross-section of the toroid gradually reduces in size to accommodate or correspond with the reduction in coil size.

In block708, the coils are sized for inserting an object within the coils. In accordance with another embodiment, the coils are configured to control an electron beam based laser. In block710, the coils and toroid are enveloped or enclosed in a diamagnetic material or a magnetic material.

In block712, an electric current supply is connected to each coils. In another embodiment a single electric current supply is configured to supply electric current to each of the coils. In accordance with a further embodiment, the electric current supply is an adjustable current supply to adjust an amplitude and/or frequency of the electric current applied to each coil for balancing the electric currents between the coils or for supplying electric current with a particular amplitude and/or frequency to each coil to provide a predetermined magnetic field distribution or magnetic flux density associated with the coils.

In block714, the magnetic field is compressed or has a highest magnetic flux density proximate a center or central region of the coils about a circumference of the toroid in response to electric current flowing in the coils. The compressed magnetic field results in a highest magnetic flux density in the center or central region of the coils compared to outside the center or central region of the coils or external to the coils. A magnitude of the magnetic field or magnetic flux density corresponds to an amplitude of the electric current flowing in the coils.

In block716, in accordance with an embodiment, magnetic resonance imaging of an object is performed using the compressed magnetic field or fields. In accordance with another embodiment non-destructive evaluation is performed on an object using the compressed magnetic field or fields or some other function is performed using the compressed magnetic field or fields. In a further embodiment, an electron beam based laser or similar laser is generated and controlled using the magnetic field or fields similar to that described in U.S. application Ser. No. 15/785,022, entitled “Apparatus and Method for Generating a High Power Energy Beam Based Laser.”

FIG. 8is a flow chart of an example of a method800for magnetic field compression in accordance with another embodiment of the present disclosure. In accordance with an embodiment, the method800is embodied in and performed by the apparatus600inFIG. 6.

In block802, a first toroid coil structure is provided and in block804, a second toroid coil structure is provided. The first toroid coil structure and the second toroid coil structure are similar to the toroid coil structures described with reference toFIGS. 3 and 6.

In block806, the second toroid coil structure is disposed adjacent the first toroid coil structure at a predetermined distance from the first toroid coil structure to form an aperture between the toroid coil structures for compression of a magnetic field. A center opening of the first toroid and the second toroid are in a same plane.

In block808, the aperture is sized for inserting an object. In accordance with another embodiment, the aperture is configured for controlling an electronic beam based laser. An example of configuring an aperture between a pair of toroid coil structures is described in more detail in U.S. application Ser. No. 15/785,022, entitled “Apparatus and Method for Generating a High Power Energy Beam Based Laser.”

In block810, the coils and toroids are enveloped or enclosed in a diamagnetic material or magnetic material.

In block812, an electric current supply is connected to each coils. In another embodiment a single electric current supply is configured to supply electric current to each of the coils. In accordance with a further embodiment, the electric current supply is an adjustable current supply to adjust an amplitude and/or frequency of the electric current applied to each coil for balancing the electric currents between the coils or for supplying electric current with a particular amplitude and/or frequency to each coil to provide a predetermined magnetic field distribution or magnetic flux density associated with the coils.

In block814, the magnetic field or fields are compression or have a highest magnetic flux density in the aperture in response to electric current flowing in the coils. The compressed magnetic fields results in a highest magnetic flux density in the aperture relative to outside the aperture or external to the toroids. A magnitude of the magnetic field or magnetic flux density corresponds to an amplitude of the electric current flowing in the coils.

In block816, in accordance with an embodiment, magnetic resonance imaging of an object is performed using the compressed magnetic field or fields. In accordance with another embodiment non-destructive evaluation is performed on an object using the compressed magnetic field or fields or some other function is performed using the compressed magnetic field or fields. In a further embodiment, an electron beam based laser or similar laser is generated and controlled using the magnetic field or fields similar to that described in U.S. application Ser. No. 15/785,022, entitled “Apparatus and Method for Generating a High Power Energy Beam Based Laser.”

In accordance with exemplary embodiments, the apparatuses and methods described herein are usable as part of a magnetic resonance image machine (not shown) for performing magnetic resonance imaging of an object, such as object122. The apparatuses and methods are applicable to non-destructive evaluation and imaging techniques, such as magnetic resonance imaging for medical purposes or other imaging applications. In another example described in U.S. application Ser. No. 15/785,022, entitled “Apparatus and Method for Generating a High Power Energy Beam Based Laser,” the object122is an electron beam, ion beam or the like that is controlled by the apparatus. Accordingly, the coils and/or aperture described herein are configured to control an electron beam, electron beam based laser, ion beam or the like. The apparatuses and methods described herein are applicable for any purpose where magnetic field compression or a high magnetic field strength or high magnetic flux up to about 10 T or higher is desired.

Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art appreciate that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown and that the embodiments have other applications in other environments. This application is intended to cover any adaptations or variations. The following claims are in no way intended to limit the scope of embodiments of the disclosure to the specific embodiments described herein.