Berlin 2001 – scientific programme

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P: Plasmaphysik

P I: HV I

P I.1: Invited Talk

Monday, April 2, 2001, 15:00–15:30, 2053

Low Temperature Plasma Physics in Fusion Research — •Detlev Reiter — Institut für Laser- und Plasmaphysik, Heinrich Heine Universität, Düsseldorf

The purity constrains for a magnetically confined, stationarily burning fusion flame demand a minimum level of particle throughput, just to remove the resulting helium ash.

The magnetic field effects and the vacuum pumping options then necessarily lead to a localization of plasma fluxes, which implies that strongly exposed parts of the furnace chamber of a fusion reactor must then be protected from overheating.

In the mid eighties the crucial role of atomic processes in the near target region in divertors was identified, first computationally and then experimentally (high recycling regime). Since then the mutual effects of plasma flows and rarefied (atomic and molecular) gas dynamics in the plasma edge regions have been intensively investigated.

The importance of phenomena typical of low temperature plasma physics has become even stronger in recent years, since edge conditions in Tokamaks are tailored to produce plasmas which recombine in the divertor volume, well in front of the target plates. In these regions the neutral gas pressure is sufficient even to break the plasma pressure balance along the magnetic field. Plasma temperatures near exposed surfaces can then fall to the one eV range, where molecular gas dynamics and chemistry start to play an essential role in the divertor behavior.

For a quantitative understanding of the physics of the plasma edge region in fusion devices, and for extrapolation to future reactors, both extensions to and adaptations of plasma diagnostics and the numerical tools used in modelling are necessary. The contribution from low temperature plasma physics to fusion research and some unsolved, fusion specific problems will be discussed.