用高效蒙特卡罗模拟器模拟电负性等离子体放电的离子能量分布

Discharge structure of Ar/Cl2 inductively coupled plasma: A cyclic study of discharge conditions at fixed power

Discharge structure refers to the morphology of different plasma quantities, such as electron temperature, reaction rate, plasma potential, mass flux, net charge and species density, which are determined by plasma transport mechanism and chemical processes. This morphology is rather difficult to refine in complex electronegative plasma for it is contained in a multiple-physics-field coupled system. Regarding this difficulty, the combination of self-consistent simulation, theory analysis and experimental diagnostic of this system is needed. In the scope of present article, the fluid simulation …

Electron power absorption dynamics in a low pressure radio frequency driven capacitively coupled discharge in oxygen

We use the one-dimensional object-oriented particle-in-cell Monte Carlo collision code oopd1 to explore the properties and the origins of both the electric field and electron power absorption within the plasma bulk for a capacitively coupled oxygen discharge operated at 10 and 100 mTorr for 45 mm of gap distance. The properties of the electric field at three different time slices as well as time averaged have been explored considering the moments of the Boltzmann equation. The electron power absorption is distinctly different at these operating pressures. The most relevant contributions to the…

Electron power absorption in low pressure capacitively coupled electronegative oxygen radio frequency plasmas

A thorough understanding of the energy transfer mechanism from the electric field to electrons is of utmost importance for optimization and control of different plasma sources and processes. This mechanism, called electron power absorption, involves complex electron dynamics in electronegative capacitively coupled plasmas (CCPs) at low pressures, that are still not fully understood. Therefore, we present a spatio-temporally resolved analysis of electron power absorption in low pressure oxygen CCPs based on the momentum balance equation derived from the Boltzmann equation. Data are obtained fro…

Equilibrium potential profile across magnetic field in inhomogeneous electronegative plasma

This paper presents the plasma potential distribution across magnetic field lines in an argon/oxygen plasma created by 13.56 MHz CCRF discharge consisting of a pair of ring electrodes. It is found that the radial plasma density, electron temperature, and plasma potential shows unusual trends as the magnetic field strength and gas pressure increase. An analytical model has been formulated to explain the radial plasma potential profile when the short-circuiting effect due to conducting boundaries can be neglected. It is found that with certain approximations, the plasma potential distribution ca…

On the Role of Metastable States in Low Pressure Oxygen Discharges

We use the one-dimensional object-oriented particle-in-cell Monte Carlo collision code {\tt oopd1} to explore the spatio-temporal evolution of the electron heating mechanism in a capacitively coupled oxygen discharge in the pressure range 10 -- 200 mTorr. The electron heating is most significant in the sheath vicinity during the sheath expansion phase. We explore how including and excluding detachment by the singlet metastable states O$_2$(a$^1 Δ_{\rm g}$) and O$_2$(b$^1Σ_{\rm g}^+$) influences the heating mechanism, the effective electron temperature and electronegativity, in the oxygen disch…

An efficient and accurate MPI based parallel simulator for streamer discharges in three dimensions

In this paper, we propose an efficient and accurate message-passing interface (MPI)-based parallel simulator for streamer discharges in three dimensions using the fluid model. First, we propose a new second-order semi-implicit scheme for the temporal discretization of the model that relaxes the dielectric relaxation time restriction. Moreover, it requires solving the Poisson-type equation only once at each time step, while the classical second-order explicit scheme typically needs to do twice. Second, we introduce a geometric multigrid preconditioned FGMRES solver that dramatically improves th…

由锯齿上升电压波形驱动的电容耦合Ar/O2放电中的电子动力学与粒子输运

Electron dynamics and particle transport in capacitively coupled Ar/O2 discharges driven by sawtooth up voltage waveforms

本研究通过流体/电子蒙特卡罗模拟，探究锯齿上升电压波形驱动的电容耦合Ar/O2放电中外部参数对电子动力学及粒子输运的影响，发现增加谐波数、降低气压和O2掺混比例可调控电负性与放电模式，并提高基片处O(1D)通量以促进沉积。

用于HL-3托卡马克中基于强化学习的控制的高保真数据驱动动力学模型

High-Fidelity Data-Driven Dynamics Model for Reinforcement Learning-based Control in HL-3 Tokamak

本文提出一种高保真完全数据驱动的动力学模型，解决了第一性原理模拟器训练强化学习缓慢的问题，在HL-3托卡马克上实现了400毫秒、1 kHz的轨迹控制，并验证了对变化目标的零样本适应能力。

TokaGrad：用于 L 到 H 全场景优化的端到端可微托卡马克模拟器

TokaGrad: End-to-end differentiable tokamak simulator for L-to-H full scenario optimization

研究聚焦聚变能源商业化下的托卡马克优化问题，提出 TokaGrad 这一可微模拟器，它整合多种可微模型，能自洽模拟全放电场景，与优化器耦合可实现多方面优化，为相关自动化、可微优化提供途径。