Bindslev, Henrik

Hoekzema, J.A.

Korsholm, Søren Bang

Leipold, Frank

Meo, Fernando

Michelsen, Poul

Michelsen, Susanne

Nielsen, Stefan Kragh

Oosterbeek, J.W.

Porte, L.

Tsakadze, Erekle

Wassenhove, G. Van

Westerhof, E.

Woskov, P.

Fast ions created in the fusion processes will provide up to 70% of the heating in ITER. To optimize heating and current drive in magnetically confined plasmas insight into fast-ion dynamics is important. First measurements of such dynamics by collective Thomson scattering (CTS) were recently reported [Bindslev , Phys. Rev. Lett. 97, 205005 2006]. Here we extend the discussion of these results which were obtained at the TEXTOR tokamak. The fast ions are generated by neutral-beam injection and ion-cyclotron resonance heating. The CTS system uses 100-150 kW of 110-GHz gyrotron probing radiation which scatters off the collective plasma fluctuations driven by the fast-ion motion. The technique measures the projected one-dimensional velocity distribution of confined fast ions in the scattering volume where the probe and receiver beams cross. By shifting the scattering volume a number of scattering locations and different resolved velocity components can be measured. The temporal resolution is 4 ms while the spatial resolution is similar to 10 cm depending on the scattering geometry. Fast-ion velocity distributions in a variety of scenarios are measured, including the evolution of the velocity distribution after turnoff of the ion heating. These results are in close agreement with numerical simulations

Online Research Database In Technology

Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

http://orbit.dtu.dk/ws/files/4813169/Nielsen.pdf

Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

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Online Research Database In Technology