O. P. Bardsley J. L. Baker
Power exhaust is a critical challenge for spherical tokamak reactors, making the design, optimisation and control of advanced divertor configurations crucial. These tasks are greatly simplified if the poloidal magnetic fields in the core and divertor regions can be varied independently. We present a novel method which fixes the core plasma equil…
Preprint PublishedP.-Y. Li D. R. Hatch B. Chapman-Oplopoiou S. Saarelma C. M. Roach M. Kotschenreuther S. M. Mahajan the MAST Team
The results of a recent gyrokinetic analysis of turbulent transport driven by the electron temperature gradient (ETG) in the MAST pedestal are presented. During the inter-ELM period, the buildup rate of the electron density gradients is faster than that of the electron temperature gradients, possibly indicating the presence of an active electron th…
PreprintV.G. Kiptily P.J. Bonofiglo T. Craciunescu J. Eriksson M. Fitzgerald V. Goloborodko M. Nocente S. Menmuir M. Podestà M. Poradzinski D. Rigamonti Z. Stancar S.E. Sharapov H. Sun D.M. Taylor M. Tardocchi P. Beaumont F. Belli F.E. Cecil C.D. Challis R. Coelho M. Curuia R. Dumont J. Garcia M. Garcia-Munoz Z. Ghani Ye. Kazakov D. Keeling E. Lerche C.F. Maggi J. Mailloux P. Mantica M.J. Mantsinen D. Marocco C. Perez von Thun F. Rimini
The fusion reaction between deuterium and tritium, D(T,n)4He is the main source of energy in future thermonuclear reactors. Charged fusion products of this reaction, α-particles (4He-ions), are born with an average energy of 3.5 MeV. Transferring energy to the thermal plasma during their slowing down, the…
PreprintPeng Shi Yuhan Wang Li Gao Hongjuan Sun Qinghu Yang Xin Xu Chengshuo Shen Yanqiu Chen Qinlin Tao Zhipeng Cheng Haosheng Wu Lu Wang Zhongyong Chen Nengchao Wang Zhoujun Yang Jingchun Li Yonghua Ding Yuan Pan J-TEXT team
This article presents an in-depth study of the sequence of events leading to density limit disruption in J-TEXT tokamak plasmas, with an emphasis on boudary turbulent transport and the high-field-side high-density (HFSHD) front. These phenomena were extensively investigated by using Langmuir probe and Polarimeter-interferometer diagnostics. The res…
PreprintD. Brunetti J. P. Graves C. J. Ham S. Saarelma
We propose a resistivity-beta driving mechanism aimed at explaining the appearance of free boundary long wavelength global instabilities in high-beta diverted tokamaks. These perturbations resemble very closely the RWM (resistive wall mode) phenomenon. Performing a proper toroidal analysis, we show that the magnetohydrodynamic stability is worsened…
PreprintJ W Berkery S A Sabbagh C Ham V Zamkovska J Butt J Riquezes M Tobin S Henderson L Kogan B Patel R Scannell E Trier B LeBlanc
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 …
Preprint PurchaseJ. Pittard N. Fox A. Hollingsworth M. Lavrentiev A. Wohlers Y. Zayachuk
Diamond’s intrinsic hardness, excellent thermal conductivity and low atomic number make it a highly promising candidate as a plasma facing material. However, as with the previously used graphite, concerns over tritium retention and resultant chemical etching have so far limited research interest in the use of synthetic diamond. In order to study …
Preprint PurchaseJ. Hargreaves H. Tipping J.C. Eloi L. Harding H. Dominguez Andrade H. Dawson T.L Martin
Severe plasma transients such as disruptions will impose high magnitude, short duration thermal loads on the plasma-facing first wall of the EU’s DEMOnstration tokamak. Repeated over DEMO’s lifetime, these transients may cumulatively alter the microstructure of first wall structural materials, degrading their performance. The effects of repeate…
Preprint PublishedD. Kumar R. Clark T. Martin M. Zimina P. Andresen L. Volpe R. Burrows
The UK National Nuclear Laboratory (NNL) has been developing its capability in high‑temperature water corrosion over the past years in collaboration with the University of Bristol, UK. As part of this work, studies have been undertaken on nuclear fusion‑specific material Eurofer‑97, a reduced activation ferritic‑martensitic steel. Eurofe…
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