Room 1.011

Institute of Aerodynamics and Gas Dynamics

Pfaffenwaldring 21

70569 Stuttgart

Germany

# Research topics

- Electromagnetic wave propagation
- Rarefied plasma flows
- High performance computing (HPC)
- Simulation of gyrotrons (a high power microwave source)
- Simulation of electric space propulsion

# Research description

For heating and diagnostics of nuclear fusion plasma, high power microwave sources – gyrotrons – are used. State-of-the-art gyrotrons provide microwave output at frequencies around 100-200GHz at powers of more the 1 MW. These microwaves are generated by an electron beam inside a cavity. The generated wave modes are then converted in a waveguide to assume an approximately Gaussian shape for further beam transmission to the reactor.

The three-dimensional simulation of the microwave-generation through the so-called Electron-Cyclotron Maser Instability is one of the main topics in the electromagnetic simulation research at IAG. The numerical method used for these simulations is the Particle-In-Cell (PIC) method. The PIC solver couples the movement of charged particles with a grid-based discontinuous Galerkin (DG) method for the numerical solution of the Maxwell equations. With this approach, electromagnetic interactions between charged particles can be simulated.

Another focus is the three-dimensional simulations inside the mode converter of a gyrotron. In this case, only the DG Maxwell-solver is used.

Another simulation field is the flow inside electric space propulsion devices. These can also be treated using the PIC method. However, the PIC solver has to be extended for these applications to include a treatment of elastic and inelastic collisions of charged as well as non-charged particles.

Due to the large memory and computational demands of the above mentioned simulations, the efficient use of parallel computation is an integral part of the research and development efforts in this field.