Abstract: A magnetic resonance imaging (MRI) system having an open superconducting magnet system (1) includes a number of horizontally oriented superconducting coils (3–10) in a cryogenic container (11). The cryogenic container contains a liquid cooling medium for cooling the superconducting coils which are located within the cryogenic container. At its top, the cryogenic container is provided with a recondensor (23) for continuously liquefying the cooling medium. The magnet system has a circuit for guiding the liquid cooling medium from the recondensor along at least part of the superconducting coils.

Abstract: A magnetic field generating device comprising a frame about which a current carrying coil of conductor is wound. The frame preferably includes spaced-apart side panels and an auxiliary supplementary cooling system panel. Each of the panels is configured with a plurality of spacers and/or perforations to facilitate and encourage the movement of air within the apparatus. The spacers are preferably provided on the interior surfaces of the primary panels to maintain the coil winding in a centered position therewith. Spacers may also be interpositioned between the various layers of the coil itself to enable airflow into and around the various coil layers. Of course, in the alternate embodiment a plurality of coils may be provided such that each individual layers or combination thereof may comprise an individual coil.

Abstract: A new type of coil magnet in which the plane of each turn of the conducting coil is rotated with respect to the central axis. This results in the induced magnetic field being oriented off the central axis. A set of two such disk assemblies are preferably nested, with the current flowing in opposite directions within the two assemblies. This results in the components of the two induced magnetic fields lying along the center axis canceling each other out, leaving only a purely transverse magnetic field. In addition, variations in the angular offset of the nested coils can be used to create a magnetic field having almost any orientation. Three or more such nested disk assemblies can be employed to strengthen and adjust the transverse magnetic field.

Abstract: A magnetic device which is highly durable, reliable, and safe without being damaged when a magnetic filed is applied. The magnetic device includes a cooling device having a cold head refrigerated by an effect of a cryogenic refrigerator, a magnetic field generation device configured to apply a non-stationary magnetic field on a magnetic body, and a cold head extension portion configured to thermally connect the magnetic body and the cold head. The cold head extension portion includes at least two members, one a low resistance member and the other a high resistance member having different resistivities. With this device, the eddy current generated in the cold head extension portion and the electromagnetic force produced in the cold head by the cold head extension portion are reduced.

Abstract: Effect of vibration of a refrigerator on a superconducting coil is reduced to reduce disturbance in an image. A coolant tank for supplying a coolant to coil containers is provided separately from the coil containers, and the refrigerator is placed in the coolant tank, and a coolant circulation passage connects between the coolant tank and the coil containers.

Abstract: A cryostat is formed into a donut form, where a cylindrical or a square concave is formed in the center of the cryostat of the superconductive magnet apparatus for an open type MRI apparatus, and the cryo-compressor is disposed in the concave.

Abstract: A directly cooled magnetic coil, particularly a gradient coil for a magnetic resonance apparatus, has the conductors forming the windings which are provided with an inner cooling channel for conducting a cooling fluid therethrough, and the conductors are fashioned as profiled segment conductors whose individual profiled segments surround a cooling tube. The cooling tube is composed of material that is not electrically conductive, or is only slightly electrically conductive, particularly a flexible plastic.

Abstract: A temperature control system for a permanent magnetic assembly in a permanent magnetic system comprises thermoelectric heat pumping devices which are in thermal contact with a yoke of the permanent magnet system. The heat pumping devices are controlled by an electronic circuit which controls the current that flows through them, so that the desired temperature of the permanent magnetic assemblies is achieved. Each thermoelectric heat pumping device includes a spring-loaded plunger which is mounted in a hole in the yoke. Heat is exchanged from or to the yoke via ambient air by natural convection or by forced air. Alternatively heat may be exchanged from the yoke via a cooling water circuit.

Abstract: A high temperature superconductor (HTSC) 5 is magnetized between drive coils 1,2 forming poles of a magnet connected by an iron yoke 9 by relative movement of a vacuum insulated cryostat 4 containing the HTSC and the magnetizing magnet, in order to magnetize a large area of HTSC using a magnet with a small region 3 of magnetizing flux. Alternatively, the HTSC 5may be contained in an evacuated region of a cryostat containing the magnetizing magnet. An interconnecting chamber allows the HTSC to be moved between an operative region and a magnetizing region without substantial loss of vacuum.

Abstract: A cold head is disposed in an insulating container and cooled by a refrigerator. A superconductor is disposed in the insulating container, contacting the cold head, and is cooled to its superconduction transition temperature or lower by heat conduction. A magnetizing coil is disposed outside the insulating container for applying a magnetic field to the superconductor. Control is performed so that a magnetic field determined considering the magnetic field to be captured by the superconductor is applied. A pulsed magnetic field is applied to the superconductor a plurality of times. Each pulsed magnetic field is applied when the temperature of the superconductor is a predetermined temperature or lower. A maximum pulsed magnetic field is applied at least once in an initial or intermediate stage of the repeated application of pulsed magnetic fields. After that, a pulsed magnetic field equal to or less than the maximum pulsed magnetic field is applied.

Abstract: A magnet, such as an open magnetic-resonance-imaging (MRI) magnet) has a first assembly including a superconductive main coil and a magnetizable pole piece which, during magnet operation, has a temperature equal to generally the temperature of the main coil. In one example, a cryogenic-fluid (e.g., liquid helium) dewar encloses the main coil, and the dewar has an interior surface defined in part by a surface portion of the pole piece. A method for providing a homogeneous imaging volume for a magnet includes steps to construct the above-described magnet.

Abstract: A superconducting magnet assembly having two individual magnetic coils contained in separate vacuum jackets with a radiation shield between each magnet and its respective vacuum jacket. Each magnet coil is cooled to superconducting temperature by direct coupling to the second stage of a separate two stage closed cycle refrigerator. A first stage of each refrigerator cools an associated radiation shield.

Abstract: A magnetic resonance imaging magnet for examining a patient comprises ferromagnetic pole pieces defining a patient-receiving gap for examining a patient. Coil assemblies for producing a magnetic field include at least one coil mounted adjacent to at least one thermally conductive member.

Abstract: A magnet, such as an open or closed magnet, has a first assembly with at least one superconductive main coil and with a first vacuum enclosure enclosing the main coil(s). A first cryocooler coldhead has a rigid first housing and is generally vertically aligned. A first flexible bellows is vertically aligned, has a first end attached to the first housing of the first cryocooler coldhead and has a second end attached to the first vacuum enclosure of the first assembly.

Abstract: In order to provide a magnetic field stabilization method, magnetic field generating apparatus and magnetic resonance imaging apparatus that is not affected by the temperature distribution in an installation space, in stabilizing a magnetic field of a magnetic field generating apparatus 2 having a pair of permanent magnets facing each other with a space interposed and yokes constituting a magnetic circuit for the permanent magnets, heat quantities to be applied to a plurality of positions are individually controlled (172, 174) based on the temperatures detected at a plurality of positions 154, 158 on the yoke to stabilize the respective temperatures at the plurality of positions.

Abstract: A magnet, such as an open or closed magnet, has a first assembly with at least one superconductive main coil and with a first vacuum enclosure enclosing the main coil(s). A first cryocooler coldhead has a rigid first housing and is generally vertically aligned. A first flexible bellows is vertically aligned, has a first end attached to the first housing of the first cryocooler coldhead and has a second end attached to the first vacuum enclosure of the first assembly.

Abstract: A coil for magnetizing an article. The coil includes a cooling coil component and an electric coil component. An elongate electric coil component is placed with its center along a bobbin, wherein one end is wound in one direction around the bobbin and the other end in the other direction. The cooling coil component includes a disk-like member in which a passage is formed for carrying a fluid coolant. The disk-like member is "C" shaped to substantially prevent the flow of eddy currents. Electric coil components disposed at the ends of the coil are provided with a greater number of windings to make the magnetic field in the coil more uniform.

Abstract: A superconducting magnet apparatus including a superconducting coil for generating a magnetic field, a radiation shield surrounding the superconducting coil, a refrigerator for cooling the superconducting coil, and a cryostat provided inside the radiation shield to store a coolant cooled by the refrigerator, wherein the cryostat is thermally connected to the superconducting coil.

Abstract: A structure of a superconducting coil capable of improving cooling efficiency is provided. The superconducting coil is formed by stacking a plurality of double pancake coils with each other. The double pancake coils are stacked in the direction of a coil axis. A cooling plate is arranged between the double pancake coils.

Abstract: An open architecture recondensing superconducting magnet utilizing an upper and lower cryogen vessel connected by a passageway which extends above the bottom of upper cryogen vessel to discontinue the flow of liquid cryogen through the passageway to reserve liquid cryogen in the upper cryogen vessel when the cryogen level falls to provide an increased ride-through period in the event of a depleting liquid cryogen supply due to failure of the cryogen gas recondenser. A signal is provided to indicate the need to correct the failure.

Abstract: A superconductor device which including a magnet coil assembly and support structures. The magnet coil assembly consists of superconducting wire which is encased in a composite structure along with an integral thermal interface. This combination forms the magnet coil assembly. The magnet coil assembly is cooled to an operating temperature of about 5K with a conductive cooling device that physically connects with the thermal interface integral to the magnet coil assembly. A cold-to-warm support structure supports the magnet coil assembly within a vacuum vessel while thermally isolating it from the external environment Structurally, the magnet coil assembly is cylindrically shaped and positioned within a toriodal shaped thermal shield which is positioned within a toroidal shaped vacuum vessel. The cold-to-warm support structure supports the magnet coil assembly spaced apart from the thermal shield. The cold-to-warm support structure includes a tapered section and an annular section.

Abstract: An open magnet useful in magnetic resonance imaging (MRI) applications. The magnet has two spaced-apart assemblies. Each assembly has a shielding coil located longitudinally outward from a main coil and a magnetizable pole piece spaced apart from and proximate the main and shielding coils. The method of the invention generates a magnetic field in a first area between the two assemblies while shielding a second area not between the two assemblies from a stray magnetic field by creating the previously-described open magnet.

Abstract: An MR imaging apparatus includes a magnet assembly having two generally opposed pole pieces. Current flowing in driver coils associated with each pole pieces generates a magnetic field in the imaging region. The driver coils include a conductor having beveled edges, the conductor being wound in a spiral fashion. A layer of electrical insulation is located between the conductor windings. A cooling member fabricated from bifilar wound tubing having a generally rectangular cross section is in thermal communication with each driver coil. Coolant flowing through the cooling member removes heat generated in the driver coils.

Abstract: A recondensing zero boiloff superconducting magnet assembly utilizing a cryocooler with a compressible indium gasket positioned between the cryocooler and the recondenser and with the gasket containing a plurality of spaced parallel grid wires with interconnecting web segments of a lesser thickness interconnecting the mid sections of ends of adjacent wires to facilitate compression of the gasket to control improved thermal conductivity while minimizing the pressure and forces on the assembly.

Abstract: An NMR measuring device contains an NMR probe head (10a) having an NMR receiver coil (11), and the probe head can be supplied via a cryogenically insulated transfer conduit (9) with coolant from a cooling device (1a). The cooling device comprises a cryo-cooler (2) having a first cooling stage (4) with a first stage exchanger (12) and a second cooling stage (3) having a second stage exchanger (8). A pump (6) transports coolant in the cooling circuit. The NMR probe head (10a), in addition to the NMR receiver coils (11), has preamplifiers (21) for amplifying the received NMR signals and an additional cryogenically insulated transfer conduit (20) is inserted between the cooling device (1a) and the NMR probe head (10a) by means of which, the preamplifiers (21) and/or the components in contact with the preamplifiers (21) can be supplied with a flow of coolant at a higher temperature than that used for cooling the NMR receiver coils (11).

Abstract: Apparatus for polarizing a multipole permanent magnet having a main surface is disclosed. The apparatus includes a support member for supporting the magnet; and conductive tubular elements in the form of a coil, the tubular elements being mounted on the support member in relation to the magnet so that the tubular elements produce a magnetizing field across the surface of the magnet to polarize such magnet when the tubular elements are energized. The apparatus further includes circuitry for energizing the tubular elements to produce the magnetizing field to polarize the magnet, and a structure for circulating coolant through the tubular elements to limit the heat build-up of the tubular elements when the tubular elements are energized.

Abstract: A passive non-electric pressure control system for a superconducting magnet cryogen vessel to maintain internal pressure above the outside pressure to avoid cryopumping utilizes a passive thermal conductor extending from the outside atmosphere into the vessel. The selective amount of penetration of the thermal conductor into the cryogen vessel controls the amount of heat transferred to the interior of the vessel and thus controls the internal pressure of the vessel.

Abstract: A superconducting magnet device and magnetizing device for superconductor including a coil provided around the superconductor; a current supply line connected to the coil and a power source and supplying a pulse current from the power source to the coil; and a refrigerant container controlled to a superconducting transition temperature or below, the coil arranged in the refrigerant container, the current supply line provided within refrigerant pipes connecting to the refrigerant container, its applied instrument, and a magnetizing method for superconductor including cooling the interior of the refrigerant container down to the superconducting transition temperature or below; supplying a pulse current to the coil for generating a magnetic field by the coil; and magnetizing the superconductor.

Abstract: A method for operating a superconductive magnet having a superconductor. The magnet is ramped to generally the design current. After that, the magnet is brought to an annealing temperature which is above the operating temperature and below the critical temperature. After that, the magnet is shimmed at a shimming temperature which is at least as cold as the annealing temperature. After that, the magnet is used, at the operating temperature, for a predetermined purpose, such as MRI imaging for medical diagnosis. Preferably, the superconductor has less than twenty-five superconductive filaments.

Abstract: A superconducting deflection electromagnet apparatus for deflecting an electron beam includes a liquid helium reservoir 21 disposed outside of the magnetic shield 11 surrounding the cryostat 4 accommodating the upper and lower liquid helium containers 2 in which coil assemblies 1, 31, 32 are disposed. Preferably, the upper and lower liquid helium containers 2 are supported from the cryostat 4 by means of the thermally insulating support members 5, 6 and 8 whose positions are adjustable by means of the threaded projections 5a, 6a and 8a and the nuts 52, 53, 62, 63, 82, 83 engaging therewith. The nuts secure the respective thermally insulating support members to the cap-shaped fixing members 44, 47, 49 attached to the extensions 43, 45, 49 of the cryostat 4.

Abstract: In order to achieve improved mechanical properties for a coil (1), it is proposed to structure a first electroconductive winding (3) of the coil (1) as a coil former. This coil has a first connecting element (15), to which a second connecting element (17) is attached via an insulating part (25). The two connecting elements (15, 17) form the connections for the coil (1). In this way, a self-supporting coil structure is achieved. The coil (1) is particularly intended as an undervoltage winding with a low number of windings for cast resin transformers.

Abstract: A superconductive lead assembly for a superconductive device (e.g., magnet) cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end flexibly, dielectrically, and thermally connected to the first stage and a second end flexibly, dielectrically, and thermally connected to the second stage. A jacket of open cell material (e.g., polystyrene foam) is in general surrounding compressive contact with the first ceramic superconductive lead, and a rigid support tube generally surrounds the jacket. This protects the first ceramic superconductive lead against shock and vibration while in the device. The rigid support tube has a first end and a second end, with the second end thermally connectable to the second stage.

Abstract: A superconductive lead assembly for a superconductive device (e.g., magnet) cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end flexibly, dielectrically, and thermally connected to the first stage and a second end flexibly, dielectrically, and thermally connected to the second stage. A jacket of open cell material (e.g., polystyrene foam) is in general surrounding compressive contact with the first ceramic superconductive lead, and a rigid support tube generally surrounds the jacket. This protects the first ceramic superconductive lead against shock and vibration while in the device. The rigid support tube has a first end and a second end, with the second end thermally connectable to the second stage.

Abstract: A method of cooling the coil of an electromagnetic riveter includes bringing a transducer into contact with the coil and transferring heat from the coil to the transducer by conduction. The heat is removed from the transducer by unconditioned plant air blown across a set of fins in the sides of the transducer.

Abstract: A superconductive lead assembly for a superconductive device (e.g., magnet) cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end flexibly, dielectrically, and thermally connected to the first stage and a second end flexibly, dielectrically, and thermally connected to the second stage. A jacket of open cell material (e.g., polystyrene foam) is in general surrounding compressive contact with the first ceramic superconductive lead, and a rigid support tube generally surrounds the jacket. This protects the first ceramic superconductive lead against shock and vibration while in the device. The rigid support tube has a first end and a second end, with the second end thermally connectable to the second stage.

Abstract: A superconductive lead assembly for a superconductive device (e.g., magnet) cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end flexibly, dielectrically, and thermally connected to the first stage and a second end flexibly, dielectrically, and thermally connected to the second stage. A jacket of open cell material (e.g., polystyrene foam) is in general surrounding compressive contact with the first ceramic superconductive lead, and a rigid support tube generally surrounds the jacket. This protects the first ceramic superconductive lead against shock and vibration while in the device. The rigid support tube has a first end and a second end, with the second end thermally connectable to the second stage.

Abstract: A cryostat assembly having an outer vessel within which is provided substantially upright inner vessel for containing an item, such as an electromagnet, to be cooled. The inner vessel is suspended from the outer vessel by a number of low thermal conductivity support members secured at one end to points on the outer vessel corresponding to the height of the center of gravity of the assembly and an item in use and at the other end to the inner vessel at points not higher than the said points on the outer vessel.

Abstract: An electromagnetic dispenser for dispensing viscous heated fluids, such as hot melt adhesives. A fixed pole extends from a fluid chamber. The coil is located about a portion of the fixed pole and spaced from the fluid chamber to isolate the coil from the fluid flow path of the adhesive. The coil is insulated from the heat which is conducted from the adhesive as well as provided with a heat sink for dissipating heat. A plunger is mounted within the fluid chamber for reciprocal movement therein to open and close dispensing orifice in response to the field generated by the coil. When mounted to a service block, the coil assembly may be serviced without disconnecting the dispenser body from the source of heated fluid.

Abstract: A permanent magnet assembly used for creating a uniform magnetic field across a portion of an air gap has a permanent magnet grouping, including a first, principal magnet, a pole piece contacting said principal magnet, and a set of auxiliary magnets extending about the periphery of the pole piece. Two such magnet groupings are positioned within a test chamber, separated a spacer, with the magnet groupings and the chamber defining the air gap across which the magnetic field extends. The strength and uniformity of the magnetic field is adjusted by including a second set of auxiliary permanent magnets or a set of electromagnetic shim coils positioned within the air gap surrounding and overtapping a portion of the air gap. Further adjustment of the magnetic field is accomplished shaping the front surfaces of the pole pieces, thus affecting the shape and direction of the resulting magnetic field.

Abstract: A beam member which is installed at diametral portion in a ring shape superconducting coil container for supporting hoop stress of the coil, or a portion of radiant heat shield covering the beam member, is partly or entirely composed of electrical insulators or high resistivity materials. In accordance with the above composition, eddy current which is generated in the coil container when the superconducting coil container crosses magnetic field caused by eddy current which is generated in the radiant heat shield when the radiant heat shield crosses strong magnetic field caused by the superconducting coils with relative vibration of the radiant heat shield to the superconducting coil by a dynamic cause can be suppressed. Accordingly, heat generation in the superconducting coil container can be reduced, and consequently, generation of quenching can be prevented.

Abstract: An apparatus for cooling the coil of an electromagnetic riveter includes a transducer which is brought into intimate contact with the coil to transfer heat from the coil to the transducer by conduction. The transducer is cooled by unconditioned plant air blown across a set of fins in the sides of the transducer.

Abstract: A superconducting apparatus is provided with windings having superconducting wires wound in a plurality of turns, and a cryostat housing the windings so as to cool the windings in a superconducting state. The superconducting wires disposed at the outer and inner peripheral areas of the windings are selected to be highly stabilized superconducting wires such that, even if frictional heat is conducted towards the windings, the highly stabilized superconducting wires are very less quenched and in turn the possibility of the quenching of the overall windings is extremely low. Further, good heat conductors are provided on the radially outer and inner of the windings. Frictional heat which flows towards the windings is transmitted into the good heat conductors in the circumferential direction, and is dissipated midway during the heat conduction. As a result, the introduction of the frictional heat into the windings is avoided and in consequence no quenching occurs in the superconducting wires.

Abstract: A magneto repulsion electrical tape wound coil has been developed with improved current distribution and improved heat transfer. The coil is easy and is expensive to manufacture and simple to mount. The coil comprises a conductive strip (e.g., a copper strip) with rectangular openings stamped in it with a standard metal stamp. The single row of openings are at regular intervals and arranged so that the width of the openings and the spacing of the openings is such that when the coil is wound there is an overlap of the openings, forming radial passages extending from the outer periphery of the coil to its central core electrode. Cooling fluid may be supplied from a hollow inner electrode so that the cooling fluid flows radially, outwardly. Since the openings overlap to form radial passages, a cross-flow path for the cooling fluid may be established where fluid enters the passages on one side of the coil and exits from the other side of the coil.

Abstract: There is disclosed a coil structure which can be rapidly energized or excited, and which reduces the generation of heat in a coil container by an eddy current due to a dynamic disturbance such as vibration and a magnetic field fluctuation, thereby suppressing the occurrence a quench. The coil container is constituted by a low-resistivity material, and a high-resistivity portion is provided at at least one portion of the coil container in the direction of the periphery of the coil container. The high-resistivity portion is provided at a position where a vibration displacement is small or a magnetic field fluctuation is small. When the coil structure is to be energized or excited, the eddy current produced in the direction of the periphery of the superconducting-coil container can be reduced at the high-resistivity portion, and when the dynamic disturbance develops, the generation of heat by the eddy current is suppressed by the low-resistivity material.

Abstract: Disclosed herein is a method of using an oxide superconducting conductor in a state including a transition region between a superconducting state and a normal conducting state, i.e., a flux flow state, by supplying the oxide superconducting conductor with a current exceeding its critical current. The oxide superconducting conductor can be used as a current lead for a superconducting magnet or the like, to extremely reduce current loss as compared with a conventional current lead of copper.

Abstract: A permanent magnet assembly used for creating a uniform magnetic field across a portion of an air gap has a permanent magnet grouping, including a first, principal magnet, a pole piece contacting said principal magnet, and a set of auxiliary magnets extending about the periphery of the pole piece. Two such magnet groupings are positioned within a test chamber, separated a spacer, with the magnet groupings and the chamber defining the air gap across which the magnetic field extends. The strength and uniformity of the magnetic field is adjusted by including a second set of auxiliary permanent magnets or a set of electromagnetic shim coils positioned within the air gap surrounding and overtapping a portion of the air gap. Further adjustment of the magnetic field is accomplished shaping the front surfaces of the pole pieces, thus affecting the shape and direction of the resulting magnetic field.

Abstract: A tape wound coil is provided, for use in magnetic repulsion punching, that has a plurality of slits therein which allow circulation of coolant therethrough. This coil is made of thin copper foil, or the like that is treated with an epoxy, for electrical insulation between the windings, and then wound around a center post. The face of the coil is machined smooth, whereas a counter bore is machined into the back of the coil such that a portion of the center post and the inner most windings are removed. Radial slits are then machined into the back of the coil, which will allow for the coolant flow. Thus, a coil for use in magnetic repulsion punching is provided which maximizes the capacity for carrying electrical current and increases the winding density exhibited by conventional M-R coils. Further, the coil of the present invention will withstand high repetition mechanical shear forces created as a result of the large amount of electrical current pulsing through the windings.

Abstract: A coil of superconducting wire for a superconducting magnet having a relaely dense and uniformly spaced winding to enhance the homogeneity and strength of the magnetic field surrounding the coil and a method of winding the same wherein the mandrel used to wind said coil comprises removable spacers and retainers forming a plurality of outwardly opening slots, each of said slots extending generally about the periphery of the mandrel and being sized to receive and outwardly align and retain successive turns of the superconducting wire within each slot as the wire is wound around and laterally across the mandrel to form a plurality of wire ribbons of a predetermined thickness laterally across the mandrel.

Abstract: A charged particle beam system utilizes a box-shaped cooling member accommodating the lens in order to cool the particle-optical lenses. The cooling medium is circulated between the wall of the lens and the wall of the cooling member, enabling a high transfer of heat by convection. By using a cooling liquid which is undersaturated for air and which is heated prior to its passage through the cooling duct, accumulation of air due to heating can be prevented in the cooling member.

Abstract: A superconducting magnet is formed having composite conductors arrayed in coils having turns which lie on a surface defining substantially a frustum of a cone. The conical angle with respect to the central axis is preferably selected such that the magnetic pressure on the coil at the widest portion of the cone is substantially zero. The magnet structure is adapted for use as an energy storage magnet mounted in an earthen trench or tunnel where the strength the surrounding soil is lower at the top of the trench or tunnel than at the bottom. The composite conductor may be formed having a ripple shape to minimize stresses during charge up and discharge and has a shape for each ripple selected such that the conductor undergoes a minimum amount of bending during the charge and discharge cycle.