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UKAEA-CCFE-PR(24)2152024
The first observations and classification of sub-cyclotron frequency range Alfvén eigenmodes (AEs) are presented for the MAST Upgrade tokamak. Sets of observed eigenmodes are separated by approximately 200 kHz. We observe a low frequency separation of ~10 kHz within the set, and the toroidal mode number n increases with frequency sequentially. …
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UKAEA-CCFE-PR(25)2882023
Dedicated experiments were performed in JET DTE2 plasmas for obtaining α-particle bump-on-tail (BOT) distribution aiming at exciting Alfvén Eigenmodes (AEs) in baseline tokamak plasma scenario with safety factor q(0)~1. NBI-only heating with modulated power was used so that fusion-born α-particles were the only ions present in the MeV energy ran…
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UKAEA-CCFE-PR(25)2872023
Fast-particle driven Alfvén Eigenmodes have been observed in low-collisionality discharges with off-axis neutral beam injection (NBI), electron cyclotron resonance heating (ECRH) and a reduced toroidal magnetic field. During NBI and ECRH, toroidicity induced Alfvén Eigenmodes (TAEs) appear in frequency bands close to 200 kHz and energetic-part…
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UKAEA-CCFE-PR(25)2862023
A forward modeling technique is developed for determining the characteristic features of observed MHD modes from the line-of-sight data of the soft x-ray (SXR) diagnostics with 64 vertical lines-of-sight in theTokamak `a Configuration Variable tokamak. Using diagnostics with excellent spatial resolution, this technique is shown to evaluate the polo…
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UKAEA-CCFE-PR(23)1302023
A Toroidal Alfven eigenmode (TAE) has been observed to be driven by alpha particles in a JET deuterium-tritium internal transport barrier plasma. The observation occurred 50ms after the removal of neutral beam heating (NBI). The mode is observed on magnetics, soft-xray, interferometry and reflectometry measurements. We present detailed stability…
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UKAEA-CCFE-PR(23)1292023
The Joint European Torus recently carried out an experimental campaign using a plasma consisting of both deuterium (D) and tritium (T). We observed a high-frequency mode using a reflectometer and an interferometer in a D-T plasma heated with low power neutral beam injection, PNBI = 11.6MW. This mode was observed at a frequency f = 156kHz and was lo…
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UKAEA-CCFE-PR(23)022023
A toroidal Alfven eigenmode (TAE) has been observed driven by alpha particles in the Joint European Torus (JET). The observation was made in dedicated deuterium-tritium experiments where radio-frequency (RF) heating was absent, in the so-called “afterglow” period when neutral beam heating was removed. Agreement with reduced and perturbative mod…
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UKAEA-CCFE-CP(23)442022
Due to their relatively higher Vbeam/VAlvén ratio, spherical tokamaks are ideal to investigate high-frequency modes such as Compressional Alfvén Eigenmodes (CAEs) and Global Alfvén Eigenmodes (GAEs), and so they have been previously studied in MAST [1, 2]. Besides, the recently installed scintillator-based Fast-Ion Loss …
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UKAEA-CCFE-CP(23)312021
Alfvén eigenmode (AE) instabilities driven by α-particles have been observed in D-3He fusion experiments on the Joint European Torus (JET) with the ITER-like wall [Kiptily et al, submitted to Phys. Rev. Letters, 2020]. The impact of these type instabilities on a burning plasma is of crucial relevance for the perfor…
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UKAEA-CCFE-PR(21)782021
Alfvén eigenmode (AE) instabilities driven by alpha-particles have been observed in D-3He fusion experiments on the Joint European Torus (JET) with the ITER-like wall (ILW). For the efficient generation of fusion alpha-particles from D-3He fusion reaction, the 3‑ion radio frequency (RF) scenario was used t…
Showing 1 - 10 of 12 UKAEA Paper Results