Characterization of Gun Plasma Penetrated Into a Steady State Plasma Device

Increase in the energy absorption of pulsed plasma by the formation of tungsten nanostructure

“…Furthermore, the responses of the nanostructured W sample to the plasmoid were investigated with this temperature measurement system. To evaluate the heat load accurately, energy deposited on W was calculated from the temperature increase of the backside surface, which was not exposed to the plasma, as no need exists to consider the changes of the emissivity of W. In this paper, NAGDIS-PG (NAGoya DIvertor Simulator with Plasma Gun), which can produce pulsed plasma (plasmoid) in addition to steady-state plasma [17,18], was used for the experiments. It is shown that the fuzzy nanostructure formation on the surface significantly alters the heat deposition from the plasma.…”

“…Helium gas was used for the discharges. An interferometer measurement system has been installed in the NAGDIS-PG device [18], and the temporal evolution of averaged density can be measured at 0.45 m away from the target. In a later discussion of the temperature calculation, we assume a triangle-shaped heat load with the duration of 0.25 ms based on the temporal evolution of the measured density.…”

“…The temporal evolutions of the calculated front surface temper ature, T sf , and T sb , and the heat loads used in the simulation are shown in figure 6. The pulsed shape is set to be a triangle with rising and falling times of 60 and 190 μs, respectively, based on the temporal evolution of the density measured previously [18]. The energy density was assumed to be 0.15 MJ m −2 , with which the calculated rear surface temperature becomes comparable to the measured value.…”