[發布]VSim9發布與新特征介紹

發布日期:2018-9-7 22:27:49 來源: BTIT

Tech-X公司發布 9 軟件

VSim 9 • 多物理場電磁自洽帶電粒子仿真軟件


VSim 軟件采用時域有限差分(FDTD)、粒子雲網格(particle-in-cell (PIC))、有限體積、直接蒙特卡洛(DSMC)方法,對天線、光子學器件、真空電子器件、二次電子倍增、濺射、激光等離子體互作用等進行建模。

VSim9擴展了可視化建模的功能,直觀的樹狀仿真流程能夠對幾何實體進行選擇和布爾操作,能夠導入STEP、STL、POLY、VTK等CAD模型文件。可視化設置使碰撞等離子體與實體互作用以及高階電磁求解器的定義更容易。

VSim 9引入非時間計數器方法對更廣泛的反應快速建模。新版VSim特點包括:對表麵場的計算更精確;提高二次發射功能;新的發射診斷功能;增加了新的電介質求解器;新的光子器件案例。

VSim9增加了更多的後處理分析器,包括S參數計算和腔體品質因數等。增加了十幾個微波放大器、光子器件、等離子體放電案例以降低初學者的使用門檻。增加了多種診斷功能收集1D/2D/3D粒子和場數據用於後處理。

VSim能夠使用Python函數輸入複雜表達式來定義邊界條件、場和粒子密度。根據波長設置網格分辨率和吸收邊界大小。定義電磁源的空間和時間特征以研究特定的模式或頻率範圍。構建模型的同時在可視化設置窗口中顯示幾何體、粒子源、電流源等。

數據分析

VSim提供了大量分析器用於仿真數據的後處理,例如:

1)         頻率和模式提取

2)         S參數計算

3)         數據分組

4)         粒子密度測量

5)         遠場計算

6)         利用預置的模板自定義分析器

相空間分析

場分析

數據分析窗口

數據可視化

除數據分析外,VSim提供基於並行算法的3D數據可視化,用戶可以疊加顯示場、粒子和網格;支持對數據的旋轉、縮放、平移、切片、隨時間演化操作。

疊加顯示場、粒子與網格


數據分組


曆史數據記錄,包括粒子、電流、電壓、能量等

應用--光子學

光子學仿真用於工程、微納技術領域。對光子晶體和等離子激元結構進行建模。模擬波導、Y結、耦合器、微環、微盤、諧振器等。


AWG

應用--複雜環境天線

VSim能夠仿真包含等離子體和電介質的複雜天線完整自洽的物理特性。等離子體由粒子或線性響應函數建模。電介質建模為二階精度。

貼片天線

應用--射頻微波設備

VSim能夠計算射頻微波發生裝置的性能,而無需實際的裝置構造。優化色散和衰減並調整行波管的功率輸出。計算射頻腔的正常模式及其頻率。

螺旋線行波管色散

應用--二次電子倍增

通過在一次運行中掃描多個功率水平,準確模擬二次電子倍增效應。每個粒子都有一個縮放參數,可以將電磁場倍增,允許多個功率或電壓同時存在。導入外部場和自定義表麵發射,並跟蹤電子。可以導入預置或自定義的二次發射模型。

二次電子倍增透視

應用--濺射

VSim提供一套強大的工具,模擬磁控濺射設備中的侵蝕和沉積。圖形化建模方便設置電離、激發、散射、濺射、二次發射和許多其它互作用。包括外部電路反饋建模、導入外場、粒子分布和用戶自建幾何模型等功能。

磁控濺射

應用--空間科學

VSim用於各種電推進器放電研究、預測不同空間環境中的航天器的表麵電荷積累效應,其中離子源可以由太陽風或電推進器等離子體羽流產生。

衛星表麵充電效應

應用--離子源

VSim強大的自洽靜電求解器可精確計算離子源內的電位,並可模擬流體代碼無法實現的效應。跟蹤粒子以研究等離子體的演變。使用圖形化界麵構造實體幾何或者導入CAD幾何體。

潘寧離子源


VSim軟件的模塊

VSim提供了高標準的電磁和等離子體動力學模擬工具。使用尖端的高性能算法設計和分析高達數百萬波長的三維設備。包括帶電和中性粒子的動力學建模與自洽電磁場和靜電場求解。隱格式模擬中性和帶電場以及它們與粒子的動力學相互作用。組合VSim不同模塊來定製模擬環境。使用VSimEM模塊來求解高Q腔場,然後用VSimMD模塊來研究場發射。從眾多內置自帶案例模擬開始,演示經典物理問題和現實設備。自帶案例涵蓋電容耦合等離子體放電CCP、霍爾/離子推進器、衛星表麵充電、雷達天線、速調管、螺旋行波管、波分複用器、光子結構等。修改自帶案例或使用可視界麵從頭開始建模來滿足實際需要。

VSimEM模塊

天線、靜電、光子、散射、比吸收率(SAR) … …

用於高端電磁場和電磁波問題研究;

電磁波在各種複雜介質中傳播;

在目標上的散射模擬,如光子晶體研究;

雷達和天線設計;諧振腔腔體設計;

電磁波在目標上的吸收。

VSimMD模塊

腔體、波導、二次電子倍增、… …

用於真空粒子束微波源及微波器件研究;

粒子束在真空腔體中傳播及與腔內電磁波相互作用的仿真,如各種真空微波源(磁控管,行波管,速調管,回旋管等)及其附屬器件(電子槍,磁聚焦係統,收集器,耦合器等)的設計優化;

器件二次電子倍增(Multipacting)過程仿真。

VSimPD模塊

用於放電等離子源及材料處理研究;

低氣壓射頻-直流等離子體源(如磁控濺射,CCP,空心陰極);

小尺寸大氣壓放電(如介質阻擋放電)設備的研究和設計;

粒子束和背景氣體的相互作用;

研究借助放電過程工作的設備,如等離子體推進器、擊穿效應、沿麵閃絡 … …


VSimPA模塊

激光尾場加速、質子束加速、… …

高強度激光場下等離子體的運動及其對激光的反作用,如激光的聚焦、整形和衍射、高能粒子的形成、靶麵物理等;

強激光與等離子體物理方麵的研究,例如激光等離子體加速器、慣性約束聚變等。





各模塊功能特征分布

VSim各模塊包括特征分布表

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

電磁場

Explicit electromagnetics

Current sources

Charge densities

Conducting slab boundaries

Slab isotropic dielectrics

Auxiliary differential equations

表麵互作用

Absorbing slab boundaries

Emitting slab boundaries

網格

Cylindrical coordinates

Spatially varying grid

Moving Window

靜態場求解

Electrostatics

Magnetostatics—including nonlinear and anisotropic

後處理

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框架能處理各種隨機過程,諸如粒子間的隨機相互作用、量子隧穿電離等。VSim可以用完全的動力學過程(宏粒子之間的碰撞)、與流體相結合的部分動力學過程(宏粒子和背景流體之間的碰撞)或非動力學過程(流體)來考慮這些相互作用。MonteCarloInteractions主要用來仿真氣體放電和激光與等離子體相互作用過程中涉及的各種反應。

VSim9增加了新的Reactions框架統一實現了各種碰撞過程的蒙特卡洛建模,包括常規的電子-離子-原子碰撞、兩體-三體複合、電子附著、激發態的產生和衰變等。Reactions框架現在支持非各向同性的散射截麵分布,並支持一般的自定義兩體碰撞模型。利用空碰撞方法,Reactions碰撞的執行速度更快。同種宏粒子之間的彈性散射和激發過程現在可以處理,對於中性(主要是惰性氣體)原子,可以進行DSMC流動模擬。



碰撞類型與模塊分布





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 locations, the surface normal at that locations, 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

專業電磁粒子仿真軟件

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