A. Matejunas L. Fletcher L. Lamberson
Due to the strong rate dependence in their mechanical response, polymers find widespread use in applications subject to impact loading. However, characterizing these materials on microsecond time scales has proven challenging. Traditional experimental techniques rely on satisfying a number of limiting assumptions and typically do not provide direct…
PreprintD. Kennedy M. Giacomin B. S. Patel W. A. Hornsby D. Dickinson C. M. Roach
We present herein the results of a linear gyrokinetic analysis of electromagnetic microinstabilites in the conceptual high−β, reactor-scale, tight-aspect-ratio tokamak STEP (Spherical Tokamak for Energy Production, https://step.ukaea.uk). We examine a range of flux surfaces between the deep core and the pedestal top for the two candidate flat…
Preprint PublishedM. Giacomin D. Kennedy C. J. Ajay D. Dickinson B. S. Patel C. M. Roach
In this work, we present the results of first-of-their-kind nonlinear local gyrokinetic simulations of electromagnetic turbulence at mid-radius in the burning plasma phase of the conceptual high-β, reactor-scale, tight-aspect-ratio tokamak STEP (Spherical Tokamak for Energy Production). A prior linear analysis in D.Kennedy et al. submitted to Nucl…
PreprintAndre Farinha Salua Hamaza Guy Bouroughes Mirko Kovac
Wireless Sensor Networks (WSN) have been shown to improve data gathering processes over large spacial and temporal scales at a low cost [1], as well as the automation of decision making processes in complex industrial settings [2]. The nuclear sector is no exception to this, being obvious applications structural health monitoring [3] and radiation…
PreprintS Henderson M Bernert D Brida M Cavedon P David R Dux O Fevrier A Jarvinen A Kallenbach R McDermott M O Mullane
This paper addresses two key issues regarding plasma exhaust in future fusion reactors. Firstly, using newly developed spectroscopic models to measure the divertor concentration of Ne and Ar, it is shown that the experimental detachment threshold on ASDEX Upgrade with Ar-only, an Ar+N mixture, and a Ne+N mixture scales as expected in comparison wit…
Preprint PurchaseCarmen Makepeace
Fuel retention in the JET-ITER like wall (JET-ILW) has decreased by a factor of 20 compared to operation with a carbon wall [1]. The reduction in retention is due largely to the decrease in chemical erosion of the beryllium main chamber. A reduction in co-deposition of fuel with beryllium has previously been reported in the divertor [2]. However…
Preprint PublishedJ.F. Rivero-Rodriguez J. Galdon-Quiroga J. Dominguez-Palacios M. Garcia-Muñoz D. Garcia-Vallejo J. Gonzalez-Martin K. McClements L. Sanchis K. Sarkimaki A. Snicker Y. Todo L. Velarde E. Viezzer
Observations of enhanced fast-ion losses during edge localized modes (ELMs) have been reported in the ASDEX Upgrade tokamak, revealing losses above the injection energy. This suggests that fast ions can be accelerated and lost by the ELMs. Recent analysis delves into the analysis of the ELM-induced losses, suggesting that the fast ions are los…
Preprint PublishedV.H. Hall-Chen F.I. Parra J.C. Hillesheim J. Ruiz Ruiz N.A. Crocker P. Shi H.S. Chu S.J. Freethy L.A. Kogan W.A. Peebles Q.T. Pratt T.L. Rhodes K. Ronald R. Scannell D.C. Speirs S. Storment J. Trisno
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…
PreprintS.M. Kaye J.W. Connor C.M. Roach
In this paper, we review the confinement and transport properties observed and predicted in low aspect ratio tokamaks, or spherical tokamaks (STs), which can depart significantly from those observed at higher aspect ratio. In particular, thermal energy confinement scalings show a strong, near linear dependence of energy confinement time on toroidal…
Preprint PublishedS B L Chislett-McDonald E Surrey J Naish A Turner D P Hampshire
All high field superconductors producing magnetic fields above 12 T are brittle. Nevertheless, they will probably be the materials of choice in commercial tokamaks because the fusion power density in a tokamak scales as the fourth power of magnetic field. Here we propose using robust, ductile superconductors during the reactor commissioning phase i…
Preprint