Development of a magnetic mirror device to explore basic plasma sciences relevant to fusion, space and astrophysical plasmas is presented. A large diameter (> 200 mm) plasma emitter, which utilizes thermionic- thermoelectronic emission from a mixture of LaB6 (Lanthanum- hexaboride) and beta-eucryptite (lithium type aluminosylicate) powders, is employed as a plasma source because of its production ability of fully ionized plasma and controllability of plasma emission rate. The plasma emitter was installed and investigation of its characteristics is started. The employment of beta-eucryptite in plasma emitter is the first experimental test because such investigation of beta-eucryptite has previously been used only for Li + ion source. Our plan for magnetized plasma experiments and results of the plasma emitter investigation is presented.