Molecular dynamics studies of temperature effects on low energy helium bombardments on tungsten surfaces

Li, Min; Wang, Jun; Hou, Qing

doi:10.1016/j.jnucmat.2012.01.008

Cited by 26 publications

(13 citation statements)

References 21 publications

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“…This is a key problem, as He bubbles increase the retention of tritium in the wall, drastically influencing the long-term thermomechanical stability and creating a large radioactive inventory, with hazardous consequences and a significant increase in fuel costs. Moreover, experiments have shown that a fuzzlike nanostructure develops on the W surface under the operating conditions (temperature, He impact energy, and He flux) expected for ITER's divertor, which increases the nucleation of bubbles, the retention of hydrogen isotopes, and the production of high-Z dust [5,6].While numerous computational studies have examined He-W interactions [7][8][9][10][11][12][13][14], these correspond to unrealistically high He uptake scenarios as compared to typical experimental conditions [15]. The impact of such high rates on the microstructural evolution is unclear.…”

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confidence: 99%

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Competing Kinetics and He Bubble Morphology in W

et al. 2015

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The growth process of He bubbles in W is investigated using molecular dynamics and parallel replica dynamics for growth rates spanning 6 orders of magnitude. Fast and slow growth regimes are defined relative to typical diffusion hopping times of W interstitials around the He bubble. Slow growth rates allow the diffusion of interstitials around the bubble, favoring the biased growth of the bubble towards the surface. In contrast, at fast growth rates interstitials do not have time to diffuse around the bubble, leading to a more isotropic growth and increasing the surface damage.

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confidence: 99%

“…While numerous computational studies have examined He-W interactions [7][8][9][10][11][12][13][14], these correspond to unrealistically high He uptake scenarios as compared to typical experimental conditions [15]. The impact of such high rates on the microstructural evolution is unclear.…”

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confidence: 99%

Competing Kinetics and He Bubble Morphology in W

et al. 2015

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“…Borovikov et al [7] studied this topic via MD simulations, significantly extending the scope of previous computational efforts [8] by considering the effect of temperature in the substrate (300 K, 1000 K, and 1500 K), incidence energy Ei (≤100 eV), deposition angles θi (0–75∘), and substrate surface orientation ((100), (110), and (310)). The interaction between W atoms was determined by an Ackland–Thetford potential [9], modified at short distances by Juslin and Wirth [10].…”

Section: Reflection and Implantation Of He Atomsmentioning

confidence: 99%

An Overview of Recent Standard and Accelerated Molecular Dynamics Simulations of Helium Behavior in Tungsten

et al. 2019

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One of the most critical challenges for the successful adoption of nuclear fusion power corresponds to plasma-facing materials. Due to its favorable properties in this context (low sputtering yield, high thermal conductivity, high melting point, among others), tungsten is a leading candidate material. Nevertheless, tungsten is affected by the plasma and fusion byproducts. Irradiation by helium nuclei, in particular, strongly modifies the surface structure by a synergy of processes, whose origin is the nucleation and growth of helium bubbles. In this review, we present recent advances in the understanding of helium effects in tungsten from a simulational approach based on accelerated molecular dynamics, which emphasizes the use of realistic parameters, as are expected in experimental and operational fusion power conditions.

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“…It has been shown above that the gain of GPU-based MD simulations is not significant if the system size is smaller than ten thousand, especially when multiple GPUs are used, due to the relatively increasing portion of the overhead times and the time taken by the sequential parts in the process. However, there are MD applications, in which many simulation boxes are required for statistical purposes, for example, the calculations of the reflection coefficients of low-energy atoms on surfaces [32]. Many small simulation boxes can be combined into a large box but should be kept independent from each other.…”

Section: Simulations Of Many Small Boxesmentioning

confidence: 99%

Molecular dynamics simulations with many-body potentials on multiple GPUs—The implementation, package and performance

Hou

Zhou

et al. 2013

Computer Physics Communications

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Molecular dynamics (MD) is an important research tool extensively applied in materials science. Running MD on a graphics processing unit (GPU) is an attractive new approach for accelerating MD simulations. Currently, GPU implementations of MD usually run in a one-host-process-one-GPU (OHPOG) scheme. This scheme may pose a limitation on the system size that an implementation can handle due to the small device memory relative to the host memory. In this paper, we present a one-host-process-multiple-GPU (OHPMG) implementation of MD with embedded-atom-model or semi-empirical tight-binding many-body potentials.Because more device memory is available in an OHPMG process, the system size that can be handled is increased to a few million or more atoms. In comparison with the CPU implementation, in which Newton's third law is applied to improve the computational efficiency, our OHPMG implementation has achieved a 28.9x~86.0x speedup in double precision, depending on the system size, the cut-off ranges and the number of GPUs. The implementation can also handle a group of small boxes in one 2 run by combining the small boxes into a large box. This approach greatly improves the GPU computing efficiency when a large number of MD simulations for small boxes are needed for statistical purposes.

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Molecular dynamics studies of temperature effects on low energy helium bombardments on tungsten surfaces

Cited by 26 publications

References 21 publications

Competing Kinetics and He Bubble Morphology in W

Competing Kinetics and He Bubble Morphology in W

An Overview of Recent Standard and Accelerated Molecular Dynamics Simulations of Helium Behavior in Tungsten

Molecular dynamics simulations with many-body potentials on multiple GPUs—The implementation, package and performance

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