中国物理B ›› 2025, Vol. 34 ›› Issue (4): 45202-045202.doi: 10.1088/1674-1056/adacce
Molecular dynamics evaluation of self-diffusion coefficients in two-dimensional dusty plasmas
Muhammad Asif Shakoori1,†, Misbah Khan2, Haipeng Li(李海鹏)1,‡, Aamir Shahzad3, Maogang He(何茂刚)4, and Syed Ali Raza5
- 1 School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China;
2 Department of Refrigeration and Cryogenic Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China;
3 Department of Physics, Government College University Faisalabad (GCUF), Allama Iqbal Road, Faisalabad 38000, Pakistan;
4 Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education (MOE), Xi'an Jiaotong University, Xi'an 710049, China;
5 School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Molecular dynamics evaluation of self-diffusion coefficients in two-dimensional dusty plasmas
Muhammad Asif Shakoori1,†, Misbah Khan2, Haipeng Li(李海鹏)1,‡, Aamir Shahzad3, Maogang He(何茂刚)4, and Syed Ali Raza5
- 1 School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China;
2 Department of Refrigeration and Cryogenic Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China;
3 Department of Physics, Government College University Faisalabad (GCUF), Allama Iqbal Road, Faisalabad 38000, Pakistan;
4 Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education (MOE), Xi'an Jiaotong University, Xi'an 710049, China;
5 School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
摘要： We employ the Green-Kubo (G-K) and Einstein relations to estimate the self-diffusion coefficients (denoted as $D_{\rm G}$ and $D_{\rm E}$, respectively) in two-dimensional (2D) strongly coupled dusty plasmas (SC-DPs) via equilibrium molecular dynamics (EMD) simulations. $D_{\rm G}$ and $D_{\rm E}$ are computed for a broad domain of screening length ($\kappa$) and coupling parameters ($\varGamma$) along with different system sizes. It is observed that both $D_{\rm G}$ and $D_{\rm E}$ decrease linearly with increasing $\varGamma$ in warm liquid states and increase with increasing $\kappa$. In cold liquid states, the Einstein relation accurately predicts $D_{\rm E} $ in 2D SC-DPs because diffusion motion is close to normal diffusion, but the G-K relation provides overestimations of $D_{\rm G}$, because VACF indicates anomalous diffusion; thus, $D_{\rm G}$ is not accurate. Our new simulation outcomes reveal that $D_{\rm G}$ and $D_{\rm E}$ remain independent of system sizes. Furthermore, our investigations demonstrate that at higher temperatures, $D_{\rm G}$ and $D_{\rm E} $ converge, suggesting diffusion motion close to normal diffusion, while at lower temperatures, these two values diverge. We find reasonable agreement by comparing current and existing numerical, theoretical and experimental data. Moreover, when normalizing diffusion coefficients by the Einstein frequency and testing against the universal temperature scaling law, $D_{\rm G}$ deviates from theoretical curves at low temperatures and $\kappa$, whereas $D_{\rm E}$ only disagrees with theory at very small $\kappa$ ($\simeq 0.10$). These findings provide valuable insight into diagnosing dust component parameters within 2D DP systems and contribute to the broader understanding of diffusion processes in DP environments.
中图分类号: (Dusty or complex plasmas; plasma crystals)
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