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UKAEA-CCFE-CP(23)412022
The MAST-U spherical tokamak has extensive capabilities to produce and explore strongly shaped plasmas and alternative divertor configurations, especially the Super-X. Robust and accurate reconstructions of plasma equilibria are the foundation of many physics analyses, as well as being important intershot for informing operation of the tokamak. …
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UKAEA-CCFE-PR(22)862022
Doppler reflectometry, or the Doppler backscattering (DBS) diagnostic, enables the measurement of turbulent density fluctuations of intermediate length scales, typically $10 gtrsim k_perp rho_i gtrsim 1$; here $k_perp$ is the turbulence’s wavenumber and $rho_i$ is the ion gyroradius. The backscattered power is proportional to the power of the tur…
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UKAEA-CCFE-PR(22)552022
The MAST-U fusion plasma research device, the upgrade to the Mega Amp Spherical Tokamak, has recently completed its first campaign of physics operation. MAST-U operated with Ohmic, or one or two neutral beams for heating, at 400-800 kA plasma current, in conventional or “SuperX” divertor configurations. Equilibrium reconstructions provide key p…
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UKAEA-CCFE-PR(22)212022
This paper describes the development of electromagnetic plasma burn-through model. Full circuit equations describing the currents in solenoid, poloidal field coil, and toroidally conducting passive structure have been integrated into the differential equation system of the plasma energy and particle balances in DYON. This enables consistent calcula…
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UKAEA-CCFE-CP(23)202021
Disruption prediction and avoidance is critical for ITER and reactor-scale tokamaks to maintain steady plasma operation and to avoid damage to device components. The present status and results from the disruption event characterization and forecasting (DECAF) research effort are shown. The DECAF paradigm is primarily physics-based and provides q…
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UKAEA-CCFE-CP(23)152021
In preparation for high fusion plasma performance operation of the newly operating spherical tokamak MAST-U, the equilibrium and stability properties of plasmas in the MAST database, as well as projections for MAST-U, are explored. The disruption event characterization and forecasting (DECAF) code is utilized to map disruptions in MAST, particul…
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UKAEA-CCFE-PR(21)792021
Reconstructions of plasma equilibria using magnetic sensors and a Dα constraint were routine during operation of the MAST spherical tokamak, but reconstructions using kinetic profiles was not. These are necessary for stability and disruption analysis of the MAST database, as well as going forward for operation in the upgrade to the device, MAST…
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UKAEA-CCFE-PR(21)042021
In preparation for the upcoming MAST-U campaign, pedestal stability of spherical tokamaks is revisited by investigating standard H-mode discharges on MAST. As a step beyond previous studies, both ion and electron profiles are used for obtaining equilibria and a diverse set of pedestals is evaluated. Stability analysis with the ELITE and CGYRO codes…
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UKAEA-CCFE-CP(20)1012020
Disruption prediction and avoidance is critical in ITER and reactor-scale tokamaks to maintain steady plasma operation and to avoid damage to device components. The present status and results from the physics-based disruption event characterization and forecasting (DECAF) research effort are shown for multiple tokamak devices. Present analysis of K…
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UKAEA-CCFE-PR(20)672019
Disruption prediction and avoidance is a critical need for next-step tokamaks such as ITER. The Disruption Event Characterization and Forecasting Code (DECAF) is used to fully automate analysis of tokamak data to determine chains of events that lead to disruptions and to forecast their evolution allowing sufficient time for mitigation or full av…
Showing 11 - 20 of 22 UKAEA Paper Results