Dust generation mechanisms under powerful plasma impacts to the tungsten surfaces in ITER ELM simulation experiments
Dust generation mechanisms under powerful plasma impacts to the tungsten surfaces in ITER ELM simulation experiments
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DOI：
10.1016/j.jnucmat.2013.01.034
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发表时间：
2013-07
影响因子：
3.1
通讯作者：
V. Makhlaj;I. Garkusha;N. N. Aksenov-N.;A. A. Chuvilo-A.;V. Chebotarev;I. Landman;S. Malykhin;S. Pestchanyi;A. T. Pugachov
中科院分区：
文献类型：
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作者：
V. Makhlaj;I. Garkusha;N. N. Aksenov-N.;A. A. Chuvilo-A.;V. Chebotarev;I. Landman;S. Malykhin;S. Pestchanyi;A. T. Pugachov
最近，在 QSPA Kh-50 设施的托卡马克模拟实验中，已经确定了在类似 ITER ELM 的能量负载下钨表面产生灰尘的几种机制。据报道，这里有破裂和熔化。当表面上形成主要裂纹网络时，经过几次短暂的冲击后，脆性破坏占主导地位。主要裂缝的分叉导致尺寸达~30μm的灰尘颗粒喷射。当沿晶界发展细裂纹网络时，表面熔化和再凝固后也会产生灰尘。在此过程中，由于细裂纹上的毛细管张力，破坏伴随着桥的形成。接下来的撞击（即使是微弱的无熔化撞击）也会破坏这些桥梁，从而产生大量纳米尺寸的尘埃颗粒。重复等离子体脉冲后的表面改性也会导致纳米级灰尘的产生。
In recent tokamak simulation experiments with the QSPA Kh-50 facility several mechanisms of dust generation from tungsten surfaces under ITER ELM-like energy loads have been identified. Here cracking and melting are reported. The brittle destruction dominates after a few transient impacts when a network of major cracks forms on the surface. Bifurcation of major cracks results in ejection of dust particles with sizes up to ∼30μm. Dust generation occurs also after surface melting and following resolidification when fine crack networks along the grain boundaries develop. In this process the destruction is accompanied by bridge formation due to capillary tension across the fine cracks. Next impacts (even weak melt-free ones) can destroy those bridges, which produces considerable amounts of dust particles of nm-size dust. Surface modification after the repetitive plasma pulses also results in creation of nm-size dust.