Design of a 20 kW calorimetric dummy load for a 28 GHz heating system
- 28 GHz gyrotron installation for TJ-K needs high power dummy load for testing and conditioning
- Adapt existing design of cylindrical box with water-filled teflon hoses to this frequency
- Build and test design
New Solvers for the fullwave reflectometry code IPF-FD3D
- For the 2D version
- Hexagonal grid: finite difference time domain (FDTD) scheme exists for vacuum, need to add plasma effects, UPML absorbing boudary conditions
- 4th order methods: central differences in time and space AND coupling to plasma, simultaneous 4th order (simultaneous may not be possible)
Numerical investigation of poloidal correlation reflectometry
- Microwave beam sent to plasma with several receiving antennas
- Each receiving antenna defines different beam geometry, probing a different poloidal position
- Correlation of signals from different positions yields poloidal rotation direction or the pitch angle of magnetic field lines
- Turbulence from codes can be used as input for realistic scenarios
3D Simulation of the ASDEX Upgrade Interferometer for the ICRF Launcher
- 3D plasma simulation with IPF-FD3D
- Interferometer beam with large transverse plasma density gradient
- Interferometer frequency near density cutoff
- Need for optimisation of sending and receiving antennas
Investigations for quasi-optical mitre bends
- Mitre-bends are the typical waveguide components for highly oversized waveguides because they are more compact than continuous bends
- For moderately oversized waveguides, diffraction effects can partly be compensated with quasi-optical designs
- Quasi-optical mitre-bends can accurately be calculated with PROFUSION.
- The work consists of parameter studies for different ratios of wavelength and waveguide diameter and the investigation of the broadband performance.
Investigations of the imaging characteristics of waveguides with a non-trivial cross-section
- Rectangular waveguides have imaging properties, which allow the design of remote steering antennas for the heating of fusion plasmas
- The angular range is, however, limited to about +/- 12°.
- By choosing a slightly deformed waveguide cross-section, the dispersion relation of the modes can be changed, leading to a possibly enlarged steering range.
- An eigenmode solver for deformed cross sections is already available and can be used for parameters studies.