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[en] This paper explores the range of possibilities for producing super high fields with advanced superconducting magnets. Obtaining magnetic fields greater than about 18 T at the coil in a large superconducting magnet system will require advances in many areas of magnet technology. These needs are discussed and potential solutions (advanced superconductors, structural materials and design methods) evaluated. A point design for a commercial reactor with magnetic field at the coil of 24 T and fusion power of 1800 MW is presented. Critical issues and parameters for magnet design are identified. 20 refs., 9 figs., 4 tabs

[en] Steady state engineering test reactors with high field, low current operation are investigated and compared to high current, lower field concepts. Illustrative high field ETR parameters are R = 3 m, α ∼ 0.5 m, B ∼ 10 T, β = 2.2% and I = 4 MA. For similar wall loading the fusion power of an illustrative high field, low current concept could be about 50% that of a lower field device like TIBER II. This reduction could lead to a 50% decrease in tritium consumption, resulting in a substantial decrease in operating cost. Furthermore, high field operation could lead to substantially reduced current drive requirements and cost. A reduction in current drive source power on the order of 40 to 50 MW may be attainable relative to a lower field, high current design like TIBER II implying a possible cost savings on the order of $200 M. If current drive is less efficient than assumed, the savings could be even greater. Through larger β/sub p/ and aspect ratio, greater prospects for bootstrap current operation also exist. Further savings would be obtained from the reduced size of the first wall/blanket/shield system. The effects of high fields on magnet costs are very dependent on technological assumptions. Further improvements in the future may lie with advances in superconducting and structural materials

[en] The energy by which a normal zone may be created in a cryostable composite superconductor derives almost exclusively from frictional heating, which originates from the movement of conductor against insulator. The magnitude of the frictional heat pulse depends on the mechanical properties of the winding, the frictional properties of the conductor-insulator interface, and the dynamics of the slip process. Quantification of the frictional heat pulse is presently under investigation. Preliminary results are presented

[en] The stability of a composite superconductor is examined using simulated frictional movement to generate the thermal perturbation. It is found that slow stable movement, which is typical of certain insulator/metal couples, does not induce quenching, but that sudden movement precipitates a quench. A method of thermally decoupling the source of friction from the superconductor has been shown greatly to decrease the effect of conductor movement on stability. The experiments were carried out as part of the superconducting MHD magnet technology program. 8 refs

[en] A design for a magnet system for a high density high field tokamak reactor is described. In this design stress in the trunk of the toroidal field structure is significantly reduced by elimination of the central ohmic heating transformer. In addition all superconducting coils are operated in the steady state and pulsed fields are generated only by copper coils

[en] If practical high temperature superconducting ceramic magnets can be developed, there could be a significant impact on reactor design. Potential advantages include a simpler, more robust magnet design, the possibility of demountable superconducting toroidal field coils and reduced shielding requirements. The high temperature superconductors can also have very high critical fields and could provide super high field operation. This could substantially increase eta tau/sub E/ values, reduce β requirements, and improve prospects for ohmic heating to ignition. The combination of moderately high β and super high field could make DHe³ operation possible in a JET size tokamak. In this paper we discuss possibilities for test reactor designs using high temperature high field superconductors. An illustrative design has a field at the plasma of 15 T. This reduces the required β to less than 2% for DT operation. The required plasma current is 5 MA. For a reactor size of R₀ = 3.4m and a = 0.6m, the neutron wall loading is 3.3 MW/m² at β = 1.5% for DT operation and an equal amount of fusion power is produced at β = 10% for DHe³ operation. One possible mode of operation is to use ohmic heating to ignition in a DT plasma followed by thermal runaway to DHe³ temperatures. 7 refs., 1 fig., 2 tabs

[en] By using high performance resistive magnets it is possible to design a relatively compact tokamak which could achieve ignition, provide long pulse operation with Q_p > 5 and advance fusion engineering. This device could be built at the TFTR site at relatively moderate cost. Illustrative features for this type of device, referred to as LITE for long-pulse ignited test experiment, are described. Forced flow liquid nitrogen cooling at constant temperature is used to minimize the TF magnet power requirements. Illustrative parameters are a major radius of 2.7m, a maximum magnetic field on axis of 8.8T, and an average beta of 0.044

[en] Examination of the criteria governing the design of superconducting adiabatic windings shows that the extrapolation of the design of a magnet storing 6 MJ of energy to higher energies can lead to adiabatic windings of about the same size as their cryostable equivalents. The criteria considered are i) stability against the energy released by epoxy cracking, ii) quench hot-spot temperature, iii) quench voltage, iv) self-field instability and v) temperature rise due to steady heat dissipation within the winding. The dimensionality of the quench in an adiabatic winding is seen to affect the extrapolation. A winding in which the quench propagates for a significant time in three mutually perpendicular directions leads to the highest winding current densities, but to less tolerance for distributed internal dissipation. Extrapolation of operating current may be limited by self-field instability to lower values than are usual in large systems

No abstract available