New Features CST COMPUTER SIMULATION TECHNOLOGY CST COMPUTER SIMULATION TECHNOLOGY

Transcription

1 New Features 2016

2 Outline Convenience Features for PIC Visualization Keep Mesh SEE Background SEE Model Import Target Frequency PIC Solver Improvements TRK Solver Improvements

3 Visualization Standard 3D Viewer now used also for PIC plots Ribbon can now be used! Save Video Macro works as well.

4 Visualization Finding e.g. very slow particles

5 Keep Mesh Multipaction Simulation Parametersweep of input power No change of geometry Performance improvement if mesh is reused For small example: 2m 9s instead of 3m 6s

6 SEE Background Multipaction Simulation Typical setup shown below (Fill up surrounding space) SEE assigned to background were ignored Not possible anymore + Warning if defined in earlier versions No particle tab anymore

7 SEE Model Import Furman/Vaughn SEE Model conversion to Import SEE files with CST header can be imported No deletion of header necessary anymore

8 Target Frequency for WG Port Reduction of evaluated port modes Absorption of unconsidered port modes Reduction in total simulation time by factor 8.7 Mode #51 Mode #3

9 Target Frequency for WG Port Easier for the user: no VBA definition automatic setting of generalized port mode solver

10 Outline Convenience Features for PIC PIC Solver Improvements Emission Modifications GPU Improvements Mitigation of Numerical Cerenkov Noise Spatially Varying Materials TRK Solver Improvements

11 Emission Modifications All emission models where adjusted to only emit, if the kinetic energy is large enough to traverse the electromagnetic field. Important for SEE cathodes, where the previous continuous emission behaviour could cause artificial exponential particle growth.

12 GPU Improvements In most of the cases, GPU and CPU delivered exactly same result. GPU CPU Port Signals

13 GPU Improvements For very small input signals GPU float accuracy of some operations was not enough. GPU CPU Port Signals

14 GPU Improvements In 2016 this had been adjusted to double precision, such that the accuracy is equally high! GPU CPU Port Signals

15 GPU Improvements Summary GPU and CPU are identical now New GPU version is approximately 8-10% faster More Accurate + Faster Please be aware: K10 and Maxwell cards show bad double precision performance. All other cards (even old C20) are fine.

16 Mitigation of Numerical Cerenkov Noise Numerically the phase velocity for poorly resolved wavelength drops (in all PIC/FDTD codes) The particle velocity can be higher than the phase velocity of the wave leading to numerical Cerenkov noise PIC simulations can be disturbed It becomes only important for: High current densities (e.g. BWO) Long interaction regions (e.g. Klystrons)

17 Mitigation of Numerical Cerenkov Noise Macro available to estimate at which frequency the noise will occur (If the frequency is very high, it might not interfere at all)

18 Mitigation of Numerical Cerenkov Noise 1. Preferred Solution: Refine longitudinally to improve resolution of higher wavelengths 2. Alternative Solution: Special dispersion material to damp the Cerenkov noise

19 Spatially Varying Material Axial varying losses for e.g. TWT can now be applied to one single material by space map based material Splitting in different object/materials is obsolete now

20 Spatially Varying Material Loaded from Textfile via VBA

21 Outline Convenience Features for PIC PIC Solver Improvements TRK Solver Improvements Improved Current Density Plots TET TRK Solver Eigen H-Field in Gun Iteration

22 Improved Current Density Plots Homogeneous beam Before Now

23 TET TRK Solver

24 Eigen H-Field in Gun Iteration Important for High Voltage guns (~500kV), where the Eigen H-Field has a focusing effect in contrast to the Eigen E-Field. Otherwise beam expansion is overestimated.

25 Summary Convenience Features More accurate and faster GPU code Hex Tracking solver with Eigen-H Field Tetrahedral Tracking solver