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A novel augmented railgun using a permanent magnet is proposed in this paper. The effects of the permanent magnet on the magnetic field and distribution of current density have been investigated. High current densities in the railguns can lead to high local temperature and erosion of the rails. Therefore, the current densities in the rails and armature should be decreased without the reduction of the Lorentz force which is required for acceleration. For this purpose, augmentation of the magnetic field can be used as an effective method. The Finite Element Method (FEM) simulations have been applied in this article to analyze the performance of the railgun in the presence of the magnets. Two augmented railgun structures have been introduced to produce a constant external magnetic field. For both structures, augmented railgun characteristics are studied in comparison to the railgun without the augmentation. The results show that augmentation with permanent magnet increases railgun efficiency, especially in low current railguns. For pulse current source I=30kA, Lorentz force of the augmented railgun with four magnets is 2.02 times greater than the conventional railgun.
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