-
UKAEA-CCFE-PR(26)4222025
Dedicated experiments were conducted on Alfvénic instabilities in the ion sub-cyclotron frequency range excited by energetic beam ions in the MAST-Upgrade tokamak. Losses of the beam ions associated with plasma instabilities were measured with a scintillator-type fast ion lost detector (FILD), which provided a 2D image of the losses as functions o…
-
UKAEA-CCFE-PR(25)4002025
The first measurements of energetic particle-driven ion cyclotron emission (ICE) in the Mega-Amp Spherical Tokamak Upgrade (MAST-U) have been obtained by adding a high sampling rate (250MHz) capability to one coil of the existing OMAHA array, oriented to measure fluctuations in the toroidal magnetic field component. All these measurements were carr…
-
UKAEA-CCFE-PR(25)3422025
We report the observation and analysis of ion cyclotron emission (ICE) in the Wendelstein 7-X (W7-X) stellarator during discharges without a significant fast-ion population. In these experiments, ICE is observed using the strap of the ICRF antenna, while remaining undetectable on the B-dot probes during ECRH-only phases. At low electron densities, …
-
UKAEA-CCFE-CP(26)342024
The MAST-U spherical tokamak (ST) is equipped with on-axis and off-axis neutral beam injectors (NBI), external sources of super-Alfvénic fast ions that provide opportunities for studying a wide range of phenomena relevant to the physics of alpha-particles in future burning plasma devices such as STEP or ITER. High performance of MAST-U plasmas rel…
-
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. …
-
UKAEA-CCFE-CP(25)282023
MAST-U is equipped with on-axis and off-axis neutral beam injectors (NBI), external sources of super-Alfvénic fast-ions that provide opportunities for studying a wide range of phenomena relevant to the physics of alpha-particles in burning plasmas. Clear evidence of fast-ion redistribution and loss due to sawteeth (ST), fishbones (FB), long-liv…
-
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…
-
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…
-
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…
-
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…
Showing 1 - 10 of 17 UKAEA Paper Results