Showing 1 - 10 of 10 Journals Results
2020
UKAEA-CCFE-PR(20)134
K D Lawson I H Coffey F Rimini I Ksiazek
Divertor Monitoring Pulses (DiMPle) have been run in JET from the C35 campaign onwards. They provide an opportunity to study the impurity contamination of the plasma when it is limited by different surfaces within the machine, as well as the longer term behaviour of the impurities. In these discharges the plasma is first limited on the outer wall, …
Preprint Published2019
UKAEA-CCFE-PR(20)13
D Darby-Lewis J Tennyson S N Yurchenko K D Lawson
Beryllium is being adopted for plasma facing walls in fusion reactors. This has led to the observation of emissions from the A 2Π state of beryllium hydride. Use of these emissions to monitor Be erosion requires electron impact excitation rates. Cross sections for electron-impact vibrational excitation within the X 2Σ + state and vibrationally…
Preprint Published2018
UKAEA-CCFE-PR(18)68
Kerry Lawson K M Aggarwal, I H Coffey, F P Keenan, M G O'Mullane
Helium is widely used as a fuel or minority gas in laboratory fusion experiments, and will be present as ash in DT thermonuclear plasmas. It is therefore essential to have a good understanding of its atomic physics. To this end He II population modelling has been undertaken for the spectroscopic levels arising from shells with principal quantum…
Preprint Published2018
UKAEA-CCFE-PR(18)57
D. Darby-Lewis J. Tennyson, K. D. Lawson, S. N. Yurchenko, M. F. Stamp, A. Shaw, S. Brezinsek
A theoretical model for isotopologues of beryllium monohydride, BeH, BeD and BeT, A 2 Π to X 2 Σ + visible and X 2 Σ + to X 2 Σ + infrared rovibronic spectra. The MARVEL procedure is used to compute empirical rovibronic energy levels for BeH, BeD and BeT, using experimental transition data for the X 2 Σ + , A 2 Π, and C 2 Σ + states. The ene…
Preprint Published2015
CCFE-PR(15)26
K.D. Lawson M. Groth P. Belo S. Brezinsek G. Corrigan A. Czarnecka E. Delabie P. Drewelow D. Harting I. KsiaSek C.F. Maggi C. Marchetto A.G. Meigs S. Menmuir M.F. Stamp S. Wiesen JET-EFDA Contributors
A discrepancy in the divertor radiated powers between EDGE2D-EIRENE simulations, both with and without drifts, and JET-ILW experiments employing a set of NBI-heated L-mode discharges with step-wise density variation is investigated. Results from a VUV/visible poloidally scanning spectrometer are used together with bolometric measurements to determi…
Preprint Published2014
A. Czarnecka V. Bobkov I. H. Coffey L. Colas P. Jacquet K. D. Lawson E. Lerche C. Maggi M.-L. Mayoral T. Pütterich D. Van Eester JET-EFDA Contributors
Magnetically confined plasmas, such as those produced in the tokamak JET, contain measurable amounts of impurity ions produced during plasma-wall interactions (PWI) from the plasma-facing components and recessed wall areas. The impurities, including high- and mid-Z elements such as tungsten (W) from first wall tiles and nickel (Ni) from Inconel str…
Published2013
K.D. Lawson I.H. Coffey K.M. Aggarwal F.P. Keenan JET-EFDA Contributors
The main populating and depopulating mechanisms of the excited energy levels of ions in plasmas with densities
Published2012
K. D. Lawson K. M. Aggarwal I. H. Coffey F. P. Keenan R. H. G. Reid et al.
The VUV/XUV spectral region is particularly rich in lines emitted by plasmas with temperatures = 30 keV used in fusion research. Examples are presented of analyses of JET tokamak data involving C VUV/XUV radiation. In the first, the C IV divertor emission is modelled, with agreement between theory and experiment to within the measurement accuracy o…
Published1999
N. J. Peacock K. D. Lawson R. Barnsley H. Chen
An empirical procedure, ‘‘LINT,’’ for relating emission line intensities of intrinsic impurity ions to their elemental contributions to the total, bolometric, radiation loss and the volume-averaged effective ion charge, Zeff , has been developed and applied to limiter plasmas in the JET tokamak. In this article we discuss extensions to the …
Published1996