Tungsten has been used in many industrial fields such as automobile industry, medical industry and so on, because of having its high creep strength and high corrosion resistance. Recently, the W is expected to apply for divertor surface of nuclear fusion reactor to prevent of wear and tear from charged and neutral particles form plasma. In case of thermal shielding properties such as divertors, it is important to smooth the surface, but the tungsten is difficult to process because of its high hardness and susceptibility to cracking and chipping. Therefore, we focused on laser processing. Pulsed laser can produce high power density over 10¹⁵W/cm² as ablation process, while the average power relatively low. On the other hand, continuous wave (CW) laser produces continuous power, an output power became high over 10 kW.  Although the difference between CW and pulsed lasers is obvious in processing tungsten, it is necessary to gain a better understanding of which processing is more suitable for surface processing.

?In this study, we tried to smooth the tungsten plate surface by irradiating it with a high-power CW laser and a femtosecond laser which is an ultrashort pulsed laser and investigated the differences in the processing characteristics of tungsten.