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Linear induction machines (LIMs) are widely used in the electromagnetic launch systems. Based on the MgB2 type superconducting wires, a superconductive LIM with an electrodynamic type structure (EDS) is proposed in this paper. The moving primary magnetic field induces eddy current in the conductor plate and the inductive eddy magnetic field acts back on the primary field. The lift force and thrust force will be produced between the primary and the secondary. Referred to the analysis of some famous researchers’ theory and achievements, an improved method is proposed and applied to MgB2 type superconducting LIM. The calculation results are obtained and compared with finite-element analysis. The results indicate the method is practical and valid, which can lead the design and save design time. [ABSTRACT FROM PUBLISHER]

Two linear induction accelerators (LIAs) have been in operation for a number of years at the Los Alamos Dual Axis Radiographic Hydrodynamic Test (DARHT) facility. A new multipulse LIA is being developed. We have computationally investigated the beam breakup (BBU) instability in this advanced LIA. In particular, we have explored the consequences of the choice of beam injector energy and the grouping of LIA cells. We find that within the limited range of options presently under consideration for the LIA architecture, there is little adverse effect on the BBU growth. The computational tool that we used for this investigation was the beam dynamics code linear accelerator model for DARHT (LAMDA). To confirm that LAMDA was appropriate for this task, we first validated it through comparisons with the experimental BBU data acquired on the DARHT accelerators. [ABSTRACT FROM PUBLISHER]

A variable pole pitch linear induction motor (VPPLIM) is proposed as a new member of the family of electromagnetic aircraft launch system (EMALS). With proper designing of the variation of the pole pitch, the VPPLIM could accelerate the aircraft almost uniformly at the condition of the usual ac supply, avoiding the use of large-scale power electronic converters. Special considerations in the design of VPPLIM, such as the structure topology, the variation of the pole pitch, and the winding arrangement are discussed in detail in this paper. The acceleration performance of the VPPLIM fed by a constant-voltage constant-frequency supply is analyzed by means of the quasi-steady-state 2-D magnetic field model and the difference model of mover’s dynamics. A two-stage method is proposed to simulate the acceleration performance of the VPPLIM based on a 2-D thrust table of the motor achieved by the finite-element method. The calculated features of the prototype VPPLIM consist well with those expected for EMALS. [ABSTRACT FROM PUBLISHER]

Due to the achievable high force densities, permanent magnet linear machines with transverse flux configurations are gaining increased interest in electromagnetic launch (EML) applications, in which the force density demand is crucial. This paper deals with the design of a tubular transverse flux linear machine (TFLM) targeting EML applications, and the issues pertinent to its topology selection, design optimization, and thermal modeling are discussed. By overall comparison of practical topologies and technologies of the TFLM, a tubular moving-magnet topology with separated flux paths is believed to be more appropriate. Design optimization is then performed to maximize the thrust force under specific volumetric constraints. It is shown that the thrust force is more sensitive to the stator segment length, instead of the magnet thickness. Regarding the overload requirement inherent in EML systems, special focus is given on the thermal characteristics of the TFLM at overload conditions, and it is proved that the machine shows appreciable overload capability. Measurements carried out on a prototype TFLM have validated the predictions. [ABSTRACT FROM PUBLISHER]