Test models of free piston Stirling engine (FPSE) converter have been developed as heat-to-electricity power converters for a demonstration of solar heat energy utilization at the Japan Aerospace Exploration Agency (JAXA), for future aerospace applications. In the case of the FPSE, the output power of the working gas is directly used as the linear alternator input and then converted into electrical power. Therefore, the linear alternator is one of the most important devices in the FPSE. On the other hand, thermo-acoustic engine (TAE) is a technology that uses high-amplitude sound waves induced by a temperature difference. The work of the sound waves can be converted to electricity by a highly efficient linear alternator. Therefore, the linear alternator is also a key component for the TEA. To realize efficient linear alternators that are suitable for the TAE, several types of linear alternators have been designed and developed based on JAXA's FPSE technology. In this study, the performance evaluations of the linear alternators were conducted.