Radiation power of Ar torch short plasma as function of length near 100 A

Summary form only given. When reduction of waste and dissolution of iron are carried out by using arc plasma, we need to reduce the arc radiation power, because there are some cases of damaging the furnace wall due to the radiation. On the other hand, we can use it as a clean source for heating materials. In this case, it´s expected that radiation becomes greater. In both cases the radiation power from plasmas has to be precisely controlled. We measured the radiation power from a torch. The radiation power increased in proportion to the 1.8-1.0/sup th/ power of the current. The radiation power in a unit length increases with the appearance plasma length.