# 18th EMWSD (Wakis) team meeting

Europe/Zurich
6/R-018 (CERN)

### 6/R-018

#### CERN

20
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Videoconference
EMWSD team meeting
Zoom Meeting ID
62540318786
Host
Carlo Zannini
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Zoom URL

Status of the studies:
- Where are we?

First 4 months since the beginning of the PhD.  In the previous meeting, we achieved 1st milestone of implementing the 3D Maxwell Equations in Python using Finite Integration Technique (FIT) formulation proposed by T. Weilland in 1984.

- Main improvements since last meeting:

Understood the difference between primal and tilde grid and implemented it in the code so that perfect electric conductor (PEC) boundary conditions could work. This completes milestone 2 of having the PEC, Periodic and perfect magnetic conductor (PMC) boundary conditions working.

Implemented a geometry (from STL/CAD files) importer using PyVista open source package based on VTK. Now we can create a 3D model in CAD / TinkerCAD or other open source geometry editor and use it as embedded boundaries. This completes milestone 3 of having embedded boundaries from STL files. PyVista also allows for efficient and fast 3D plotting on the fields, 100x faster and less memory-consuming than matplotlib. Built-in methods have been developed to plot 3D fields in 1-line of code.

Using the STL importer, we can assign different materials to each imported solid. So far, only isotropic and constant electric permeability and magnetic permittivity can be defined. This gets us closer to milestone 5 of having non-frequency depended materials. We need to figure out how to implement conductivity to complete the milestone.

- Some fun examples:

Examples are shown as gif animations to qualitatively test the implemented boundary conditions, and the stl importer. Simulations use different initial conditions (static and time-dependent) and different materials (PEC, dielectric, vacuum).

- Feedback from university trip:

Showcased the code to my university supervisors Manuel Cotelo and Eduardo Oliva (UPM). Their expertise in electromagnetism and code development was very helpful and they provided some interesting ideas on quantitative tests for the numerical scheme used: symmetry, reflection from boundaries, dispersion, etc. We revised the internal architecture of the code and started to work on the plane wave test interacting with a sphere of different materials. Performed some heavy simulations using more than 4,000,000 cells for a few timesteps.

- Conclusions and next steps:

• Need to understand how to inject the particle beam to be able to run wakefield simulations. (milestone 4)
• Need to start to write quantitative tests and set up UNIT testing
• Need to figure out the bug on 3D initial conditions near the boundaries (cubic resonator test)
• Need a 1st benchmark with CST: cubic cavity once the beam injection is set up
• Need to start exploring Perfect Matching Layers (PML) boundary conditions (milestone 6)

There are minutes attached to this event. Show them.
• 3:30 PM 4:00 PM
Status of the studies 30m
• 4:00 PM 4:30 PM
Discussion 30m
• 4:30 PM 5:00 PM
Definition of next steps 30m