UKAEA Papers

"High Performance ITER-baseline discharges in Deuterium with nitrogen and neon-seeding in the JET-ILW"

• C. Giroud
• S. Brezinsek
• R. Pitts
• I.S. Carvalho
• A. Huber
• E. Kaveeva
• D. Keeling
• J. Mailloux
• S. Aleiferis
• B. Chapman
• S. Henderson
• L. Garzotti
• E. Lerche
• M. MArin
• M. Maslov
• M. Brix
• P. Carvalho
• I. Coffey
• J. Fontdecaba
• L. Horvath
• I. Jepu
• J. Karhunen
• E. Litherland-Smith
• A. Meigs
• R.B. Morales
• T. Pereira
• D. Refy
• Z. Stancar
• M. Sertoli
• S. Silburn
• G. Szepesi
• A. Thorman
• M. Tomes
• I. Veselova
• B. Viola
• S. Wiesen
• JET contributors,

JET has investigated one the key issues for the baseline scenario in ITER, the integration of a radiative divertor for heat load control with the use of neon and nitrogen as seed impurity. A characterization of the choice of the impurity seed on plasma confinement, neutrons, pedestal MHD stability, pedestal instabilities, core transport is given…

"Comparing pedestal structure in JET-ILW H-mode plasmas with a model for stiff ETG turbulent heat transport"

• A.R. Field
• B. Chapman
• D.R. Hatch
• C.M. Roach
• S. Saarelma
• L. Frassinetti

"Interpretation of transient bursts of ion cyclotron emission from fusion-born protons in deuterium plasmas in the Large Helical Device"

• B. C. G. Reman
• R. O. Dendy
• T. Akiyama
• M. Salewski
• S. C. Chapman
• J. W. S. Cook
• H. Igami
• S. Inagaki
• K. Saito
• R. Seki
• G. S. Yun

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…

"Understanding reactor relevant tokamak pedestals"

• C J Ham
• A Bokshi
• D Brunetti
• G Bustos Ramirez
• B Chapman
• J W Connor
• D Dickinson
• A R Field
• J P Graves
• T Kiviniemi
• S Leerink
• B McMillan
• S Newton
• S Pamela
• C M Roach
• S Saarelma
• J Simpson
• S F Smith
• P Strand
• A Virtanen
• the JET Contributors*

The pedestal plays an important role in determining the confinement in tokamak H-mode plasmas. However, the steep pressure gradients in this transport barrier also lead to edge localized modes (ELMs) [1]. There is good understanding of the pedestal in type I ELM regimes [2], however, type I ELMs are known to damage plasma facing components and f…

"Density dependence of ion cyclotron emission from deuterium plasmas in the Large Helical Device"

• B. C. G. Reman
• R. O. Dendy
• T. Akiyama
• S. C. Chapman
• J. W. S. Cook
• H. Igami
• S. Inagaki
• K. Saito
• M.H. Kim
• S.G. Thatipamula
• G. S. Yun

Ion cyclotron emission (ICE) driven by perpendicular neutral beam-injected (NBI) deuterons, together with the distinctive ICE driven by tangential NBI, have been observed from heliotron-stellarator plasmas in the Large Helical Device (LHD). Radio frequency radiation in the lower hybrid range has also been observed, with frequency dependent on plasm…

"Collective energy transfer from neutral beam-injected ions to fusion-born alpha-particles on cyclotron timescales"

• R O Dendy
• B Chapman
• B C G Reman
• J W S Cook

Observations of radiation in the ion cyclotron range of frequencies from the KSTAR tokamak and LHD heliotron-stellarator show that energetic neutral beam injected (NBI) ion populations can relax collectively in the edge plasma near the injection point. The resulting radiation is ion cyclotron emission (ICE), whose spectrum has strongly suprather…

"Effect of Non-Heisenberg Magnetic Interactions on Defects in Ferromagnetic Iron"

• Jacob Chapman
• Pui-Wai Ma
• Sergei Dudarev

Fundamental flaws in the Heisenberg Hamiltonian are highlighted in the context of its application to BCC Fe, including the particular issues arising when modelling lattice defects. Exchange integrals are evaluated using the magnetic force theorem. The bilinear exchange coupling constants are calculated for all the interacting pairs of atomic ma…

"Origin of ion cyclotron emission at the proton cyclotron frequency from the core of deuterium plasmas in the ASDEX-Upgrade tokamak"

• B Chapman
• R O Dendy
• S C Chapman
• K G McClements
• R Ochoukov

Observations have recently been made of ion cyclotron emission (ICE) that originates from the core plasma in the DIII-D and ASDEX-Upgrade tokamaks. In some of these cases, the ICE spectral peaks correspond to the local cyclotron harmonic frequencies of fusion-born ions close to the magnetic axis. This is in contrast to the hitherto usual spatial lo…

"An overview of shared technical challenges for magnetic and inertial fusion power plant development"

• Ian Chapman
• Nick Walkden

Fusion energy is an area of active development and innovation worldwide, with many design concepts exhibiting a range of technical challenges. A significant portion of technical challenges will be unique for a given design concept, however there are several overarching challenges that any design must address to some degree. These include: Tritiu…

"Interpretation of suprathermal emission at deuteron cyclotron harmonics from deuterium NBI plasmas in KSTAR"

• R O Dendy
• B Chapman
• G S Yun
• S C Chapman
• K G McClements
• S G Thatipamula
• M H Kim
• A Zalzali

Intense suprathermal radiation, with spectral peaks at multiple harmonics of the deuteron cyclotron frequency, is detected from the outer midplane edge of KSTAR deuterium plasmas that are heated by tangential neutral beam injection (NBI) of 100keV deuterons. We identify how this deuterium ion cyclotron emission (ICE) is generated, and distinguish t…