Conference paper · Journal article
Observations of core ion cyclotron emission on ASDEX Upgrade tokamak
Max Planck Institute for Plasma Physics1
University of Warwick2
University of Seville3
École polytechnique4
United Kingdom Atomic Energy Authority5
Technical University of Denmark6
Department of Physics, Technical University of Denmark7
Plasma Physics and Fusion Energy, Department of Physics, Technical University of Denmark8
The B-dot probe diagnostic suite on the ASDEX Upgrade tokamak has recently been upgraded with a new 125 MHz, 14 bit resolution digitizer to study ion cyclotron emission (ICE). While classic edge emission from the low field side plasma is often observed, we also measure waves originating from the core with fast fusion protons or beam injected deuterons being a possible emission driver.
Comparing the measured frequency values with ion cyclotron harmonics present in the plasma places the origin of this emission on the magnetic axis, with the fundamental hydrogen/second deuterium cyclotron harmonic matching the observed values. The actual values range from ∼27 MHz at the on-axis toroidal field BT = -1.79 T to ∼40 MHz at BT = -2.62 T.
When the magnetic axis position evolves during this emission, the measured frequency values track the changes in the estimated on-axis cyclotron frequency values. Core ICE is usually a transient event lasting ∼100 ms during the neutral beam startup phase. However, in some cases, core emission occurs in steady-state plasmas and lasts for longer than 1 s.
These observations suggest an attractive possibility of using a non-perturbing ICE-based diagnostic to passively monitor fusion alpha particles at the location of their birth in the plasma core, in deuterium-tritium burning devices such as ITER and DEMO.
Language: | English |
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Publisher: | AIP Publishing LLC |
Year: | 2018 |
Pages: | 10J101 |
Proceedings: | 22nd Topical Conference on High-Temperature Plasma Diagnostics |
ISSN: | 10897623 and 00346748 |
Types: | Conference paper and Journal article |
DOI: | 10.1063/1.5035180 |
ORCIDs: | Rasmussen, A.N. , 0000-0001-9879-2285 , 0000-0002-5259-9970 , 0000-0002-3241-502X , 0000-0002-4848-4898 , 0000-0002-5162-509X and 0000-0001-7626-9872 |