[发布]VSim9发布与新特征介绍

发布日期:2018-9-7 22:27:49 来源: BTIT

Tech-X公司发布 9 软件

VSim 9 • 多物理场电磁自洽带电粒子仿真软件


VSim 软件采用时域有限差分(FDTD)、粒子云网格(particle-in-cell (PIC))、有限体积、直接蒙特卡洛(DSMC)方法,对天线、光子学器件、真空电子器件、二次电子倍增、溅射、激光等离子体互作用等进行建模。

VSim9扩展了可视化建模的功能,直观的树状仿真流程能够对几何实体进行选择和布尔操作,能够导入STEP、STL、POLY、VTK等CAD模型文件。可视化设置使碰撞等离子体与实体互作用以及高阶电磁求解器的定义更容易。

VSim 9引入非时间计数器方法对更广泛的反应快速建模。新版VSim特点包括:对表面场的计算更精确;提高二次发射功能;新的发射诊断功能;增加了新的电介质求解器;新的光子器件案例。

VSim9增加了更多的后处理分析器,包括S参数计算和腔体品质因数等。增加了十几个微波放大器、光子器件、等离子体放电案例以降低初学者的使用门槛。增加了多种诊断功能收集1D/2D/3D粒子和场数据用于后处理。

VSim能够使用Python函数输入复杂表达式来定义边界条件、场和粒子密度。根据波长设置网格分辨率和吸收边界大小。定义电磁源的空间和时间特征以研究特定的模式或频率范围。构建模型的同时在可视化设置窗口中显示几何体、粒子源、电流源等。

数据分析

VSim提供了大量分析器用于仿真数据的后处理,例如:

1)         频率和模式提取

2)         S参数计算

3)         数据分组

4)         粒子密度测量

5)         远场计算

6)         利用预置的模板自定义分析器

相空间分析

场分析

数据分析窗口

数据可视化

除数据分析外,VSim提供基于并行算法的3D数据可视化,用户可以叠加显示场、粒子和网格;支持对数据的旋转、缩放、平移、切片、随时间演化操作。

叠加显示场、粒子与网格


数据分组


历史数据记录,包括粒子、电流、电压、能量等

应用--光子学

光子学仿真用于工程、微纳技术领域。对光子晶体和等离子激元结构进行建模。模拟波导、Y结、耦合器、微环、微盘、谐振器等。


AWG

应用--复杂环境天线

VSim能够仿真包含等离子体和电介质的复杂天线完整自洽的物理特性。等离子体由粒子或线性响应函数建模。电介质建模为二阶精度。

贴片天线

应用--射频微波设备

VSim能够计算射频微波发生装置的性能,而无需实际的装置构造。优化色散和衰减并调整行波管的功率输出。计算射频腔的正常模式及其频率。

螺旋线行波管色散

应用--二次电子倍增

通过在一次运行中扫描多个功率水平,准确模拟二次电子倍增效应。每个粒子都有一个缩放参数,可以将电磁场倍增,允许多个功率或电压同时存在。导入外部场和自定义表面发射,并跟踪电子。可以导入预置或自定义的二次发射模型。

二次电子倍增透视

应用--溅射

VSim提供一套强大的工具,模拟磁控溅射设备中的侵蚀和沉积。图形化建模方便设置电离、激发、散射、溅射、二次发射和许多其它互作用。包括外部电路反馈建模、导入外场、粒子分布和用户自建几何模型等功能。

磁控溅射

应用--空间科学

VSim用于各种电推进器放电研究、预测不同空间环境中的航天器的表面电荷积累效应,其中离子源可以由太阳风或电推进器等离子体羽流产生。

卫星表面充电效应

应用--离子源

VSim强大的自洽静电求解器可精确计算离子源内的电位,并可模拟流体代码无法实现的效应。跟踪粒子以研究等离子体的演变。使用图形化界面构造实体几何或者导入CAD几何体。

潘宁离子源


VSim软件的模块

VSim提供了高标准的电磁和等离子体动力学模拟工具。使用尖端的高性能算法设计和分析高达数百万波长的三维设备。包括带电和中性粒子的动力学建模与自洽电磁场和静电场求解。隐格式模拟中性和带电场以及它们与粒子的动力学相互作用。组合VSim不同模块来定制模拟环境。使用VSimEM模块来求解高Q腔场,然后用VSimMD模块来研究场发射。从众多内置自带案例模拟开始,演示经典物理问题和现实设备。自带案例涵盖电容耦合等离子体放电CCP、霍尔/离子推进器、卫星表面充电、雷达天线、速调管、螺旋行波管、波分复用器、光子结构等。修改自带案例或使用可视界面从头开始建模来满足实际需要。

VSimEM模块

天线、静电、光子、散射、比吸收率(SAR) … …

用于高端电磁场和电磁波问题研究;

电磁波在各种复杂介质中传播;

在目标上的散射模拟,如光子晶体研究;

雷达和天线设计;谐振腔腔体设计;

电磁波在目标上的吸收。

VSimMD模块

腔体、波导、二次电子倍增、… …

用于真空粒子束微波源及微波器件研究;

粒子束在真空腔体中传播及与腔内电磁波相互作用的仿真,如各种真空微波源(磁控管,行波管,速调管,回旋管等)及其附属器件(电子枪,磁聚焦系统,收集器,耦合器等)的设计优化;

器件二次电子倍增(Multipacting)过程仿真。

VSimPD模块

用于放电等离子源及材料处理研究;

低气压射频-直流等离子体源(如磁控溅射,CCP,空心阴极);

小尺寸大气压放电(如介质阻挡放电)设备的研究和设计;

粒子束和背景气体的相互作用;

研究借助放电过程工作的设备,如等离子体推进器、击穿效应、沿面闪络 … …


VSimPA模块

激光尾场加速、质子束加速、… …

高强度激光场下等离子体的运动及其对激光的反作用,如激光的聚焦、整形和衍射、高能粒子的形成、靶面物理等;

强激光与等离子体物理方面的研究,例如激光等离子体加速器、惯性约束聚变等。





各模块功能特征分布

VSim各模块包括特征分布表

功能特征

VSimEM

VSimMD

VSimPA

VSimPD

一般特征

Works in 3D-2D-1D

Distributed memory parallelism

Periodic boundaries

Histories

Prescribed fields (functional, user defined, or imported)

Open source data format with visualization annotations

粒子

Charged particles

Variably weighted charged particles

Non relativistic particles

Relativistic charged particles

Tagged particles for particle tracking

Depositors and interpolators, area weighting and 1st order

电磁场

Explicit electromagnetics

Current sources

Charge densities

Conducting slab boundaries

Slab isotropic dielectrics

Auxiliary differential equations

表面互作用

Absorbing slab boundaries

Emitting slab boundaries

网格

Cylindrical coordinates

Spatially varying grid

Moving Window

静态场求解

Electrostatics

Magnetostatics—including nonlinear and anisotropic

后处理

Particle binning

Spectrograph analysis

Customizable Python scripts

Embedded boundaries

BASIC ELECTROMAGNETICS

Dey-Mittra

Cerenkov filter

ADVANCED ELECTROMAGNETICS

Controlled dispersion

Anisotropic dielectrics

Second-order dispersive dielectrics

Linear plasma dielectric

Kirchhoff Box

Full field/scattered field

PML boundaries

MAL boundaries

Port boundaries

ADVANCED PARTICLE DYNAMICS

Field-scaled particles

Higher order particles

ADVANCED PARTICLE BOUNDARY CONDITIONS

Partially transparent absorbers

Absorbing embedded BC

Reflecting embedded BC

Collisions

Field ionization

EMITTERS

Prescribed emission

Field emission

Fowler-Nordheim emission

Thermionic emission

Space-charge limited emission

Laser-induced emission

SECONDARY EMITTERS

Electron-induced electron emission

Ion-induced secondary electron emission

Sputtering

Dynamic particle weight management

FLUIDS

Cold relativistic fluid

Static background gas

Euler fluid

DYNAMIC GRID

Boosted frame

Moving window

Envelope Model

Circuit equations

Feedback control

Electrostatics with embedded boundaries



碰撞模型

VSim中的MonteCarloInteractions框架能处理各种随机过程,诸如粒子间的随机相互作用、量子隧穿电离等。VSim可以用完全的动力学过程(宏粒子之间的碰撞)、与流体相结合的部分动力学过程(宏粒子和背景流体之间的碰撞)或非动力学过程(流体)来考虑这些相互作用。MonteCarloInteractions主要用来仿真气体放电和激光与等离子体相互作用过程中涉及的各种反应。

VSim9增加了新的Reactions框架统一实现了各种碰撞过程的蒙特卡洛建模,包括常规的电子-离子-原子碰撞、两体-三体复合、电子附着、激发态的产生和衰变等。Reactions框架现在支持非各向同性的散射截面分布,并支持一般的自定义两体碰撞模型。利用空碰撞方法,Reactions碰撞的执行速度更快。同种宏粒子之间的弹性散射和激发过程现在可以处理,对于中性(主要是惰性气体)原子,可以进行DSMC流动模拟。



碰撞类型与模块分布





VSim9 Release Notes

New and Updated VSim 9.0 Features

VSim Computational Engine (Vorpal)

A new reaction framework that has more and faster reactions was implemented. The speed of the new reaction framework comes from implementing the no-time-counter algorithm.

Previous reactions implemented with this new capability are

Ø elastic collisions

Ø charge exchange collisions

Ø electron ionization

Ø impact ionization

Ø field ionization

Ø recombination (e.g., H+ + e- -> H)

Ø 3-body recombination (e.g., H+ + e- + e- -> H + e-)

Ø electron impact dissociation (e.g., H2 + e -> H + H + e)

Ø excitation (e.g., H + H/e -> H* + H/e)

Ø dissociation (e.g., H2 + H/e -> H + H + H/e)

Ø electron attachment (e.g., H + e- -> H-)

Ø negative ion detachment (e.g., H- + H/e -> H + e- + H/e)

New reactions are

Ø dissociative ionization (e.g., H2 + e -> H+ H + e)

Ø dissociative recombination (e.g., H3+ + e -> H2 + H)

Ø general inelastic binary reaction with 2 reactants -> 2 products, momentum conserved, and a specified energy lost. (e.g., H2 + H2+ -> H3+ + H)

In addition, field ionization removes the ionization energy from the field.

One can now specify the species in fluid and particle blocks by element name, which sets the mass, charge, ionization energy, and excitation energy. Once a predefined species has been set, it is ready to be used within the rxn framework. In addition, these properties can be defined for a custom species with (species=custom) in the ptcl/fluid block. Further, one can still override the values for any species, e.g., select Hydrogen but set its ionization energy to be different from 13.8 eV.

The secondary emission process was generalized so that the impact of any species on a wall can lead to the emission of itself or any other species. (In the prior implementation, the allowance of secondary emission was determined by the order of appearance in the input file.) The user now has some control over secondary particles, including customizable weighting and tagging, as well as correlated secondary emission of multiple species.

Memory usage was reduced for electromagnetic simulations.

The computation of surface fields at boundaries was improved, making the motion of particles more accurate, even in cells that overlap the boundary.

Slab histories with reduced communication and memory usages were developed, enabling larger simulations on multicore CPUs.

The methodology for second-order dielectric updaters with conformal boundaries and dispersion was developed and implemented.

Restarts were enabled for simulations with grid boundaries having cuts at domain boundaries.

All random processes can be controlled by a seed.

There are now emitter diagnostics that record individual particle data of emitted particles as well as sums and averages over all particles emitted in each time step.

More robust cut-cell absorption with optional diagnostics recording the absorption location, the surface normal at that location, and the exact time of absorption.

VSim Analyzers

All analyzers updated to a common interface to reduce the need to look up certain individual properties.

Custom analyzer development was simplified through restructuring so that basic services (file reading, options) flow automatically.

New analyzers:

1) S Parameters from History (computeSParamsFromHists.py)

2) S Parameters from Overlap Integral Calculation (computeSParamsViaOverlapIntegral.py)

3) Compute Geometry Cavity Merit Factor G (computeCavityG.py)

4) Extract Modes via Operator (extractModesViaOperator.py)

5) Compute Accelerating Voltage and Transit Time of a Cavit Mode (computeTransitTimeFactor.py)

6) Creates Field Data on an Unstructured Mesh Representing Surface Geometry (putFieldOnSurfaceMesh.py)

The following analyzers were removed:

1) addPtclComponentKEeVx.py

2) addPtclComponentKEeVy.py

3) addPtclComponentKEeVz.py

4) annotateFieldOnLine.py

5) annotateSpeciesAbsPtclData2.py

6) calculateEmittance.py

7) calculateFieldMaxAmplitude.py

8) computeCumulativeSumHistory.py

9) computeFarFieldFourierComponent.py

10) computeFieldCrossProduct.py

11) computeLineIntegral.py

12) computePtclLimits.py

13) computeSpectrogram.py

14) computeSurfaceFlux.py

15) convertPtclComponentsCartToCylX.py

16) convertPtclComponentsCartToCylZ.py

17) createParticleTracks.py

18) exportSpecies.py

19) getFieldComponentsOnPlane.py

20) performTwoHistoryArithmetic.py

VSimComposer

The input file is now generated more quickly. Status messages have been expanded to give more detail. The Run Panel was restructured to allow all parameters to be visible at once, and to show the VSim recommendation for certain parameters, such as the time step. The Analyze Panel was restructured to allow several analyzers to be open at once, with separate output windows for each.

Visual Setup generalized to allow easier specification of many simulation parameters:

Basic Settings

1) Phase shift boundary conditions

2) Easier switching between 2D and 3D simulations

3) Decomposition direction specification

4) Dump in groups (for use by extract modes by operator)

5) Suppress dumps of certain fields

Fields

1) Expanded options for Linear Solver

2) 2nd order dielectrics, up to 9 dielectrics

3) Feedback driven ports

4) Import external VSim and function defined fields

Particles

1) Charge accumulation particle boundaries

2) Partial transmitter particle boundary

3) Diffuse reflector particle boundary

4) Monte Carlo interactions

5) Particle load From file

Collisions

1) Background gas can be a fluid

2) Specification of Charged Particles by species name as an option

3) Managed weight particles weight setting

Histories

1) Accelerating Voltage and Field Slab History

VSim Documentation

The documentation was rewritten and expanded. There are now five manuals, VSim Installation, VSim User Guide, VSim Examples, VSim Customization, and VSim Reference. The User Guide contains an extensive section on the basic concepts of simulation.

VSim Examples

VSim examples contains many new examples, in particular concerning photonics and plasma discharges. In detail:

1) a6Magnetron1Modes.sdf

2) a6Magnetron2Power.sdf

3) arrayedWaveguideGrating.sdf

4) cylFiber.sdf

5) cylindricalWaveguide.sdf

6) dielectricWaveguide.sdf

7) dielectricWaveguideMode.sdf

8) dipoleOnConductingPlane.sdf

9) microringResonator.sdf

10) microringResonatorMode.sdf

11) pillboxCavity.sdf

12) singleParticleCircularMotion.sdf

13) transportEmissionSbT.pre

Software

专业电磁粒子仿真软件

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