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MHD induced fast ion losses in ASDEX Upgrade

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					MHD Induced Fast Ion Loss Diagnostic for Alcator C-Mod
M. García-Muñoz, J. A. Snipes*
MPI für Plasmaphysik, EURATOM Association, Garching bei München, Germany *MIT Plasma Science and Fusion Center, Cambridge, MA USA

fast ions

Fast ion

3D-Collimator

vtot  v  v//
The strike points of the ions on the scintillator plate depend on their gyroradius and pitch angle (magnetic spectrometer)

Scintillator housing

The ion loss pattern is imaged by a double system:

plasma

- A CCD-camera (slow 25 Hz, but high spatial resolution 756x290 pixels) - A set of PMTs with 1 MHz overall bandwidth
Manuel García-Muñoz, Alcator C-Mod Ideas Forum, MIT PSFC, Cambridge, MA 13 – 15 December 2006

Time resolved energy and pitch angle in ASDEX-Upgrade

CCD image

Energy range • Deuterium ions from E=60 keV ( ~ 25 mm) up to E=800 keV ( ~ 110 mm) • Hydrogen ions from E=100 keV ( ~ 25 mm) up to E > 1 MeV

PMT signal
(2 MHz sampling rate)

Manuel García-Muñoz, Alcator C-Mod Ideas Forum, MIT PSFC, Cambridge, MA

13 – 15 December 2006

Time Resolved TAE Induced Fast Ion Losses
Magnetics Spectrogram Fast Ion Loss Spectrogram

 Attempt to quantify the fast ion loss due to TAEs with high time resolution

 Modeling is required to extrapolate detected signal to a total fast ion loss
Manuel García-Muñoz, Alcator C-Mod Ideas Forum, MIT PSFC, Cambridge, MA 13 – 15 December 2006

MHD Induced Fast Ion Loss Diagnostic for Alcator C-Mod Motivation: To gain physics understanding of MHD induced fast ion losses.
Exploit capabilities of TAE antennas. Can we get a direct relationship between TAE magnetic amplitude and the subsequent fast ion loss? Fast ion losses due to NTMs? ELMs? Multi-machine experiments between AUG, JET, and C-Mod. Scaling towards a quantitative prediction of the expected fast ion losses due to these modes in ITER through a comparison of experiment and modeling.

Goals: Develop and install of a new fast ion loss diagnostic for C-Mod with a
bandwidth of 2 MHz. – Direct correlation between magnetic perturbation amplitudes and the subsequent fast ion loss

Plan of execution:
– Design of the Fast Ion Loss Diagnostic for C-Mod with 1 MHz response – Installation of detector during next shut down

– Apply the existing codes (HAGIS, GOURDON, ORBIT) to compute fast ion trajectories in C-Mode plasmas with MHD activities
– Model the results with NOVA-K and compare to ITER modeling
Manuel García-Muñoz, Alcator C-Mod Ideas Forum, MIT PSFC, Cambridge, MA 13 – 15 December 2006


				
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