“…therein], LHD [31], a low-pressure Rf plasma device [17], the GLADIS device at IPP Garching [18] and also on W components in an inertial electrostatic confinement (IEC) device at the Univ. of Wisconsin [32]. Thus, He-induced W nanostructuring is seemingly device independent and is a materials issue driven by the action and accumulation of He in the elevated temperature W matrix.…”
“…therein], LHD [31], a low-pressure Rf plasma device [17], the GLADIS device at IPP Garching [18] and also on W components in an inertial electrostatic confinement (IEC) device at the Univ. of Wisconsin [32]. Thus, He-induced W nanostructuring is seemingly device independent and is a materials issue driven by the action and accumulation of He in the elevated temperature W matrix.…”
“…At the higher fluence of 5×10 22 3 He/m 2 at 1273 K, a coral morphology developed [38]. The coral morphology is a uniformly distributed porous and fibrous structure that was seen on tungsten samples previously irradiated in the HOMER and HELIOS devices [38][39][40][41]. The coral morphology is characteristically smaller than the porous structure that developed on sample S18.…”
Section: Comparison With Previous Uw-iec Experimentsmentioning
Erosion is a serious concern associated with the use of tungsten as a plasma-facing component in fusion reactors. To compare the damage progression, polycrystalline tungsten (PCW) and (110) single crystal tungsten (SCW) samples were prepared with (1) a mechanical polish (MP) with roughness values in the range of 0.018-0.020 µm and (2) an MP and electropolish (MPEP) resulting in roughness values of 0.010-0.020 µm for PCW and 0.003-0.005 µm for SCW samples. Samples were irradiated with 30 keV He + at 1173 K to fluences between 3×10 21 and 6×10 22 He/m 2 . The morphologies that developed after low-fluence bombardment were different for each type of sample-SCW MP, SCW MPEP, PCW MP, and PCW MPEP. At the highest fluence, the SCW MPEP sample lost significantly more mass and developed a different morphology than the SCW MP sample. The PCW samples developed a similar morphology and had similar mass loss at the highest fluence. Surface preparation can have a significant effect on post-irradiation morphology that should be considered for the design of future fusion reactors such as ITER and DEMO.
“…The difficulty to reproduce the plasma environment of a laser fusion reactor (short pulses, high fluence and high energy spectral ranges of X-rays and ions) is probably the reason why those studies have been so sparse and, when they have been attempted, they did not fully reproduce the adequate conditions. From the available studies, it is pertinent to mention the repetitive thermal load investigations by the Dragon Fire laser [8], the X-ray damage simulated using Z-pinch machines [9,10] and the ion effects modeled either by RHEPP I at the Sandia National Laboratories [11] or by the inertial electrostatic confinement device at the University of Wisconsin-Madison [12]. It is important to indicate that the large number of investigations on materials and test facilities available from the magnetic fusion community cannot be directly extrapolated to laser fusion due to the intrinsically different plasma conditions [13].…”
Laser fusion environments are characterized by prompt bursts of high energy neutrons, ions and X-rays which are absorbed by different components of the fusion reaction chamber. In particular, plasma facing components are subjected to extreme conditions and prior to their use in the reactors they must be validated under stringent irradiation tests. However, the particular characteristics of the fusion products, i.e. very short pulses, very high fluences and broad particle energy spectra are difficult to reproduce in test laboratories, making those validations hard to be carried out. In the present work, the ability of ultraintense lasers to create the appropriate characteristics of laser fusion bursts is addressed. A description of a possible experimental set-up to generate the appropriate ion pulses with lasers is presented. At the same time, the possibility of generating X-ray or neutron beams which reproduce those of laser fusion environments is also pointed out and assessed under current laser intensities. It is concluded that ultraintense lasers should play a relevant role in the validation of materials for laser fusion facilities and immediate action for this systematic study is called for.
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