# Research fields at TEMF

The focus of the research activities in the TEMF Laboratory is on the numerical simulation of a variety of electromagnetic phenomena, relevant in a wide spectrum of science and technology. The application field of such simulations extends from low frequency industrial applications up to high frequency technologies, from the development of electromechanical sensors to the bio-electromagnetic simulation of the human body, from the design of electronic components to the elementary particle research in accelerator physics. For such systems of high complexity, empirical models or analytical calculations generally do not provide reliable solutions. That is why the computer simulation plays a more and more important role, sustained also by the explosive development of the computer technology.

An important starting point of the research at TEMF is the Finite-Integrations-Theorie, which represents a discrete formulation for general vector differential equations, in particular for Maxwell's equations. FIT is the first discretization method of its kind and it represented a revolution in the field simulation. A decisive advantage of the FI formulation in comparison with other methods is that it represents a closed theory, which can be successfully applied to the full spectrum of the electromagnetic applications. Some important research areas at TEMF are:

**Development of numerical methods**

- Development of FIT algorithms of higher order convergence
- Development of FIT algorithms on structured, nonorthogonal Grids
- Use of spectral methods in the development of “Reduced Order” Models for the system matrices of the FI method
- Development of subgridding algorithms and adaptive discretization methods
- Development of solution algorithms for electro- and magneto-quasistatic phenomena with indefinite or singular system matrices
- Development of iterative solution algorithms for large-scale systems of equations

**Modelling **

- Improvement of the FIT geometry approximation through special material-filling methods for partially filled grid cells
- Modelling of thin perfectly conducting metal sheets with arbitrary geometry curvature
- Generation of orthogonal and nonorthogonal hexahedral meshes for the FIT method

**Applications of coupled electromagnetic fields**

- Calculation of electromagnetic fields in the human body, with bio-electromagnetic application in medicine
- Coupled field-temperature calculations of transient phenomena in lossy systems
- Fluid dynamics calculation and optimization of on-board electronic components with forced convection cooling
- Simulation of gas discharges and of the collision dynamics in plasmas
- Modelling of the emission process of charged particles from arbitrarily curved surfaces

**Low frequency applications**

- Electromechanical calculations for dynamic systems (with moving parts). Design studies for the development of electrical motors
- Magnetostatic and magneto-quasistatic field simulations with ferromagnetic materials in transformers, magnetic sensors and magnetic storage media

**Applications in high frequency technology**

- Field calculation of transmission elements and components and their coupling to network simulations
- Calculation of the farfield radiation patterns for complex antenna systems in the presence of scattering bodies, by using hybrid methods
- Time domain field simulations in dispersive and nonlinear materials, with application to optical waveguides, microwave switches and attenuation elements
- Time domain field simulation in gyrotropic materials for the development of highly accurate wavefilters

**Applications in accelerator physics**

- Development of on-line simulation tools for accelerators
- Dispersion free calculation of wake fields in accelerator cavities
- Optimization of high frequency components like input couplers and HOM couplers
- Beam dynamics simulations for today's and tomorrow's accelerator projects
- Development of simulation methods for low-energy electron beams
- Design studies of accelerating cavities for synchrotrons and storage rings
- Transient field calculations for superconducting magnets
- Investigation of higher order modes (HOM) in accelerator cavities
- Impedance calculations and optimization of accelerator modules
- Optimization of planar pick-ups and kicker electrodes
- Simulation of wake fields in the THz regime

**Visualisation**

- Implementation of the VRML technique for the visualization of three-dimensional structures and their field solutions