1 / 17

Mode Matching and Particle Studio * Comparison (with a little digression on the Wire Method)

Mode Matching and Particle Studio * Comparison (with a little digression on the Wire Method). Marco Panniello , Vittorio Giorgio Vaccaro , Naples. Carlo Zannini , CERN. * Particle Studio with the new filtering tool. Particle Studio.

cruz
Download Presentation

Mode Matching and Particle Studio * Comparison (with a little digression on the Wire Method)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Mode Matching and Particle Studio* Comparison(with a little digression on the Wire Method) Marco Panniello, Vittorio Giorgio Vaccaro, Naples. Carlo Zannini, CERN. * Particle Studio with the new filtering tool

  2. Particle Studio The results from Particle Studio seem almost insensitive to the conductivity and going up in frequency, the reliability is clearly bad. We need a shorter bunch (and then a very thin mesh) to investigate the red frequency region. σ=1mm Wake-length (WL)=3m Not reliable region, dependent by bunch length s Gaussian bunch adopted as excitation signal

  3. Particle Studio & Mode Matching Without take care of the bunch and the wakefield length there is an acceptable agreement only from 2.4 to 6.0 nwn. To reach better results, a shorter bunch (σ) and longer “wake” (WL) are needed. The bunch length and the WL must be chosen accurately during the simulation setup, to obtain reliable results by PS. σ=1mm Wake-length (WL)=3m Bad agreement region, dependent by bunch length in PS simulations.

  4. Particle Studio & Mode Matching Below cutoff, there is agreement on the resonant frequency values, but not on the peaks height. The WL determines a upper limit for the Quality Factor. σ=1mm Wake-length (WL)=3m

  5. Particle Studio & Mode Matching Changing the geometrical parameters, the remarks on the comparison between the behaviour of the two codes are the same. In the next slide it is shown the first resonance magnification for two different values of the conductivity. σ=2mm Wake-length (WL)=3m Bad agreement region, dependent by bunch length in PS simulations.

  6. Particle Studio & Mode Matching Wake-length (WL)=3m

  7. Particle Studio & Mode Matching The peak of the impedance from PS seems be constant to 2.9 kΩ, while the MM results scale according to the square root of the conductance ratio.

  8. Particle Studio & Mode Matching Pillbox: b = 15 mm; c = 43 mm; 2L = 30 mm; βγ > 1000; Remark: the values of the impedance peaks calculated by MM are proportional to the square root of the conductance ( ) ; The impedance calculated by means of PS without opportune trick, seems to be constant.

  9. A reliable Q factor by Particle Studio Increasing the WL, the accuracy in the frequency domain results improved. The accuracy is fundamental if we are interested to determine the Q and the impedance peak. Otherwise, to determine only the modes resonant frequency, it is sufficient a very short wake because it is important only to excite the modes .

  10. A reliable Q factor by Particle Studio Time and memory needed to simulate a lossy pillbox (b = 15 mm; c = 43 mm; 2L = 30 mm;), by a standard PC. It is worth of note, the large amount of memory needed to reach a relatively little Q value.

  11. A reliable Q factor by Particle Studio Qsim versus Qmax of the first resonance peak, for different conductivity values. The PS simulations tend to the SF results as the Qmax increases. For very high conductivity, PS need an unacceptable amount of time and computer memory, to allow a practical employment.

  12. A reliable Q factor by Particle Studio SX. Qsim versus Qmax of the first resonance peak, for a PEC pillbox. DX. Qsim versus resistivity, on changing the WL value.

  13. Conclusions • Particle Studio is able to effectively operate in frequency domain. • In the case of resistive wall structures (e.g. steel or Copper), it is necessary to simulate very long wakes in time domain to obtain reliable results for the Q factor. • It means to perform simulations that need a large amount of computer memory and excessive time to be accomplished. • These characteristics are more evident if compared to Mode Matching Technique performances.

  14. Real model & Virtual Measurements Steel pillbox --------------- exact evaluation --------------- Virtual measurement b=10;c=30;2L=20

  15. Real model & Virtual Measurements

  16. Real model & Virtual Measurements For this peak we performed simulations varying the wire radius. The results are reported in the next slide

  17. Real model & Virtual Measurements(Approaching the Real Model) Reducing the wire radius the results tend to the resonance of the real model. In order to converge, the radius becomes unfeasible.

More Related