Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade.

2D electron cyclotron emission imaging at ASDEX Upgrade (invited).

The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfvén eigenmode, sh...

Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited).

The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110 GHz) to resolve the one-dimensional velocity distribution of the confined fast ions. The steerable ...

Comparative Study of Sawtooth Physics and Alfvén Waves via 2-D ECE Imaging on KSTAR, DIII-D, AUG and TEXTOR

High temporal and spatial resolution 2-D images of the sawtooth crash via the upgraded Electron Cyclotron Emission Imaging (ECEI) system on Toroidal EXperiment for Technology Oriented Research (TEXTOR) tokamak plasmas revealed new information concerning the sawtooth crash process. This includes: 1) observation of a wide range of crash time scales up to the resistive time scale 2) observation of...

Electron Cyclotron Emission Radiometer Upgrade on the JET Tokamak . Electron Cyclotron Emission Radiometer Upgrade on the JET Tokamak

Ion orbit loss current in ASDEX Upgrade

The orbit loss current is calculated for the ASDEX Upgrade geometry using the 5D (3D in configuration space and 2D in velocity space) Monte Carlo code ASCOT. The balance between the obtained current and the analytical estimate of the return current shows an L–H transition for the normalized collision frequency ν∗i ≈ 1 as expected from analytic theory. The transition in ASDEX Upgrade, however, o...