• Nuclear Engineering and Technology
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• 제52권3호
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• pp.568-574
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• 2020

The feasibility of the particle-in-cell (PIC) method is assessed to simulate the non-collective phenomena like non-collective Thomson scattering (TS). The non-collective TS in the laser-plasma interaction, which is related to the single-particle behavior, is simulated through a 2D relativistic PIC code (XOOPIC). For this simulation, a non-collective TS is emitted from a 50-50 DT plasma with electron density and temperature of n_e = 3.00 × 10¹³ cm^-3 and T_e = 1000 eV, typical for the edge plasma at ITER measured by ETS system, respectively. The wavelength, intensity, and FWHM of the laser applied in the ETS system are λ_i,0 = 1.064 × 10^-4 cm, I_i = 2.24 × 10¹⁷ erg=s·㎠, and 12.00 ns, respectively. The electron density and temperature predicted by the PIC simulation, obtained from the TS scattered wave, are n_e,TS = 2.91 × 10¹³ cm^-3 and T_e,TS = 1089 eV, respectively, which are in accordance with the input values of the simulated plasma. The obtained results indicate that the ambiguities rising due to the contradiction between the PIC statistical collective mechanism caused by the super-particle concept and the non-collective nature of TS are resolved. The ability and validity to use PIC method to study the non-collective regimes are verified.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.242.1-242.1
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• 2014

The electron cyclotron resonance plasma source with a belt-type magnet assembly (BMA) is designed for effective plasma confinements. For characterizing the plasma source, the plasma parameters are measured by Langmuir probe. However, the plasma parameters and the motion of charged particles near the ECR zone are not easy to diagnostics, because of the high plasma density and temperature. Thus, as an alternative method, the electromagnetic simulation of the plasma source has been performed by using three-dimensional particle-in-cell and Monte Carlo collisional (PIC-MCC) simulation codes. For considering the limitation of simulation resources and time, the periodic boundary condition is applied and the coulomb collision is neglected. In this paper, we present the results of 3D PIC simulations of ECR plasmas with BMA and we compare them with the experimental results.

• 한국항공우주학회지
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• 제45권11호
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• pp.932-938
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• 2017

플라자마의 거동을 오일러리안 격자와 라그랑지안 입자를 혼합하여 해석하는 Particle-in-cell 기법을 적용하여 간략화된 홀추력기를 해석하였다. 본 연구는 중성입자, 이온입자 뿐만 아니라 전자도 라그랑지안 기법으로 개별추적 계산하기 때문에 message passing interface 기법을 이용해 대용량 계산이 가능한 병렬클러스터링을 적용하였다. 계산에 앞서 일정한 벡터의 자기장에서 전자군의 나선형 거동을 해석하였고, 절대해와 일치함을 확인하여 코드를 검증하였다. 실린더 내부에 반경방향으로 일정한 자기장과 축방향으로 일정한 전기장을 고정시켜 플라즈마의 거동을 PIC 모델을 이용하여 해석하였다. 반응 실린더 내부에 전자가 로렌츠 힘에 의해 이중나선을 그리며 구속되는 현상이 잘 포착되었고, 고속 회전하는 전자와 주입된 중성입자가 충돌하여 이온화 되었고, 대전된 입자가 축방향의 전기장에 의해 급 가속하는 현상 또한 잘 모사되어 플라즈마의 플룸 거동을 모사하였다.

• Journal of Astronomy and Space Sciences
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• 제32권1호
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• pp.45-50
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• 2015

We have developed a 2.5-dimensional electromagnetic particle simulation code using the particle-in-cell (PIC) method to investigate electromagnetic phenomena that occur in space plasmas. Our code is based on the leap-frog method and the centered difference method for integration and differentiation of the governing equations. We adopted the relativistic Buneman-Boris method to solve the Lorentz force equation and the Esirkepov method to calculate the current density while maintaining charge conservation. Using the developed code, we performed test simulations for electron two-stream instability and electron temperature anisotropy induced instability with the same initial parameters as used in previously reported studies. The test simulation results are almost identical with those of the previous papers.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.557-560
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• 2008

A two-dimensional particle-in-cell(PIC) simulation with a Monte-Carlo Collision(MCC) has been developed to investigate the discharge characteristics of the acceleration channel of a HET. The dynamics of electrons and ions are treated with PIC method at the time scale of electrons in order to investigate the particle transport. The densities of charged particles are coupled with Poisson's equation. Xenon neutrals are injected from the anode and experience elastic, excitation, and ionization collisions with electrons, and are scattered by ions. These collisions are simulated by using an MCC model. The effects of control parameters such as magnetic field profile, electron current density, and the applied voltage have been investigated. The secondary electron emission on the dielectric surface is also considered.

• 천문학회보
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• 제43권1호
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• pp.56.2-56.2
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• 2018

Astrophysical shocks accelerate particles to high velocities, which we observe as cosmic rays. The acceleration process changes the nature of the shock because the particles interact with the local magnetic field, removing energy and potentially triggering instabilities. In order to simulate this process, we need a computational method that can handle large scale structures while, at the same time, following the motion of individual particles. We achieve this by combining the grid magnetohydrodynamics (MHD) method with the particle-in-cell (PIC) approach. MHD can be used to simulate the thermal gas that forms the majority of the gas near the shock, while the PIC method allows us to model the interactions between the magnetic field and those particles that deviate from thermal equilibrium. Using this code, we simulate shocks at various sonic and Alfvenic Mach numbers in order to determine how the behaviour of the shock and the particles depends on local conditions.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.292-300
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• 2024

Kinetic simulations have been performed on an Inertial Electrostatic Confinement Fusion (IECF) device. These simulations were performed using the particle-in-cell (PIC) method to analyze the behavior of ions in an IEC device and the effects of some parameters on the Confinement Time (CT). CT is an essential factor that significantly contributes to the IEC's performance as a nuclear fusion device. Using the PIC method, the geometry of a two-grided device with variable grid radius, the number of cathode grid rings, variable pressure and different dielectric thickness for the feed stalk was simulated. In this research, with the development of previous works, the interaction of particles was simulated and compared with previous results. The simulation results are in good agreement with the previous results. In these simulations, it was found that with the increase of the dielectric thickness of the feed stalk, the electric field was weakened and as a result, the confinement time was reduced. On the other hand, with the increase of the cathode radius, the confinement time increased. Using the results, an IEC device can be designed with higher efficiency and more optimal CT for ions.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.43.4-44
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• 2009

electron, ion, heavy ion으로 구성 된 plasma에서 hump type과 kink type(double layer)의 electrostatic solitary waves이 존재할 수 있다는 것을 pseudopotential method를 이용한 결과와 1d PIC(Particle-In-Cell) simulation method의 결과에서 각각 확인하였다. 1d PIC simulation에서 초기에 각각의 입자 종(species; electron, ion, heavy ion)의 밀도섭동(density perturbation)은 Gaussian 형태로 주었으며, 각각의 입자들의 drift velocity는 각각의 plasma 입자 종들의 thermal velocity로 나란한 방향으로 주었다.

• 한국추진공학회지
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• 제25권4호
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• pp.1-11
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• 2021

2000년 대에 들어 가파르게 성장하고 있는 우주비행체용 전기추진시스템의 안정적인 운영기술 개발을 위해, PIC-DSMC를 이용하여 전기추력기의 배기플룸의 거동을 해석하였다. 해석 방법에서 Boltzmann 관계식을 이용한 Simple Electron Fluid Model을 적용하였고, 원자-이온 간 충돌에 의해 발생하는 전하 교환 및 운동량 교환을 함께 고려하였다. 본 연구의 해석결과는 실험에서 계측한 플라즈마 전위값을 비교적 잘 예측하였다. 추력기 출구 근처에서는 활발한 입자 간 충돌 및 원자-이온 간 전하 교환으로 인해, 느린 이온 및 빠른 원자가 생성되었으며, 추력기 배기플룸의 궤적 및 속도에 중요한 영향을 미칠 것으로 예측되었다.

• 천문학회보
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• 제41권1호
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• pp.47.2-47.2
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• 2016

The protons and helium ions in the solar wind are observed to possess anisotropic temperature profiles. The anisotropy appears to be limited by various marginal instability conditions. One of the efficient methods to investigate the global dynamics and distribution of various temperature anisotropies in the large-scale solar wind models may be that based upon the macroscopic quasi-linear approach. The present paper investigates the proton and helium ion anisotropy instabilities on the basis of comparison between the quasi-linear theory versus particle-in-cell simulation. It is found that the overall dynamical development of the particle temperatures is quite accurately reproduced by the macroscopic quasi-linear scheme. The wave energy development in time, however, shows somewhat less restrictive comparisons, indicating that while the quasi-linear method is acceptable for the particle dynamics, the wave analysis probably requires higher-order physics, such as wave-wave coupling or nonlinear wave-particle interaction. We carried out comparative studies of proton firehose instability, aperiodic ordinary mode instability, and helium ion anisotropy instability. It was found that the agreement between QL theory and PIC simulation is rather good. It means that the quasilinear approximation enjoys only a limited range of validity, especially for the wave dynamics and for the relatively high-beta regime.