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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(24)2162023
The first pedestal stability analysis on the new MAST Upgrade (MASTU) spherical tokamak H-mode plasma is presented. Our results indicate that MAST-U pedestals are close to the low toroidal mode number (n) peeling branch of the peelingballooning instability, in contrast with MAST H-mode pedestals which were deeply in the high-n ballooning branch. Th…
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UKAEA-CCFE-PR(23)1592023
Fusion power output from spherical tokamaks would benefit from increased confined plasma density, but there exists a limit on the density before confinement is lost and the plasma current is disrupted. This density limit has long been characterized by a simple, global Greenwald limit proportional to the plasma current and inversely proportional …
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UKAEA-CCFE-CP(23)042023
When RF waves are applied in tokamaks with metal walls, sheath rectification effects associated with the fields induced in the scrape-off layer (SOL) may lead to enhanced plasma-wall interactions (i.e. heat-loads in the limiters, RF-induced impurity sources) which can endanger the integrity of the machine and limit the RF power. Although many co…
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UKAEA-CCFE-PR(23)142023
Collisional-radiative models are commonly used to analyse atomic and molecular processes in low temperature plasmas by determining the distribution functions of excited states as functions of various plasma parameters. This paper outlines the improvements to a zero-dimensional collisional-radiative model, developed at Keio University, for purposes …
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UKAEA-CCFE-CP(24)062022
MAST-U is equipped with a Super-X divertor, which aims to reduce heat flux to the target and promote detachment. Measurements of plasma electron density and temperature in the Super-X chamber offer insight into the processes at work in this type of divertor. First data have been obtained from the MAST-U divertor Thomson scattering diagnostic design…
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2022
Thermal evolution and high temperature annealing of dislocation microstructure of an irradiated metal, described by an ensemble of in…
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UKAEA-CCFE-PR(25)2772021
In a snowflake (SF) divertor, two magnetic field nulls are placed close to each other, creating four strike points (SPs) compared to two in a standard X-point divertor. In preparation for MAST-U experiments, magnetic configurations with the standard and SF divertors with various locations and separation distances of the nulls were modeled using …
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UKAEA-STEP-CP(23)032021
The application of dc magnetic field to a 2G high temperature superconducting (HTS) tape can reduce the critical current Ic of the tape, without driving the material normal. This property can be used in the development of HTS switching elements through so-called Jc(B) switching. The design of a dc magnetic field switch is reported, in both singl…
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UKAEA-CCFE-PR(21)732021
During bursty MHD events, transient ion cyclotron emission (ICE) is observed from deuterium plasmas in the Large Helical Device (LHD) heliotron-stellarator. Unusually, the frequencies of the successive ICE spectral peaks are not close to integer multiples of the local cyclotron frequency of an energetic ion population in the likely emitting regi…
Showing 11 - 20 of 96 UKAEA Paper Results