Plasma injection device

Purpose: To increase the life of a plasma injection plate for use in a thermonuclear device handling high temperature plasmas. Constitution: Materials of low atom number such as Li, Be, B and C or materials containing low atom number are embedded in a metal substrate as a plasma injection plate. The low atom number materials are diffused in and segregated on the metal substrate, by which a segregation layer of the low atom number material is formed on the outer surface of the metal substrate to cover the substrate so that the metal substrate is prevented from sputtering with the collision of particles from the plasmas. Further, even if the segregated layers of the low atom number materials are consumed by sputtering, the low atom number materials embedded in the metal substrate are always diffused in or segregated on the metal substrate, whereby the low atom number materials covering the metal substrate can be supplemented. (Kawakami, Y.)