Shape coexistence in Hg

Mller-Gatermann, C.*; Dewald, A.*; Fransen, C.*; Auranen, K.*; Badran, H.*; Beckers, M.*; Blazhev, A.*; Braunroth, T.*; Cullen, D. M.*; Fruet, G.*; et al.

Physical Review C, 99(5), p.054325_1 - 054325_7, 2019/05

https://doi.org/10.1103/PhysRevC.99.054325

no abstracts in English

Progress at JET in integrating ITER-relevant core and edge plasmas within the constraints of an ITER-like wall

Giroud, C.*; Jachmich, S.*; Jacquet, P.*; Jrvinen, A.*; Lerche, E.*; Rimini, F.*; Aho-Mantila, L.*; Aiba, Nobuyuki; Balboa, I.*; Belo, P.*; et al.

Plasma Physics and Controlled Fusion, 57(3), p.035004_1 - 035004_20, 2015/03

https://doi.org/10.1088/0741-3335/57/3/035004

This paper reports the progress made at JET-ILW on integrating the requirements of the reference ITER baseline scenario with normalized confinement factor of 1, at a normalized pressure of 1.8 together with partially detached divertor whilst maintaining these conditions over many energy confinement times. The 2.5 MA high triangularity ELMy H-modes are studied with two different divertor configurations with D-gas injection and nitrogen seeding. The power load reduction with N seeding is reported. The relationship between an increase in energy confinement and pedestal pressure with triangularity is investigated. The operational space of both plasma configurations is studied together with the ELM energy losses and stability of the pedestal of unseeded and seeded plasmas.

Edge pedestal characteristics in JET and JT-60U tokamaks under variable toroidal field ripple

Urano, Hajime; Saibene, G.*; Oyama, Naoyuki; Parail, V.*; de Vries, P.*; Sartori, R.*; Kamada, Yutaka; Kamiya, Kensaku; Loarte, A.*; Lnnroth, J.*; et al.

Nuclear Fusion, 51(11), p.113004_1 - 113004_10, 2011/11

https://doi.org/10.1088/0029-5515/51/11/113004

The effect of TF ripple on the edge pedestal characteristics are examined in JET and JT-60U. By the installation of ferritic inserts, TF ripple was reduced from to in JT-60U. In JET, TF ripple was varied from to by feeding different currents to TF coils. The pedestal pressure was similar with reduced ripple in JT-60U. In JET, no clear difference of the pedestal characteristics was also observed. The edge toroidal rotation clearly decreased in counter direction by increased TF ripple. However, in JT-60U, the ELM frequency decreased by and the increased ELM loss power by with reduced ripple. In JET, ELM frequency increases only slightly with increased TF ripple. From this inter-machine experiment, TF ripple less than does not strongly affect the pedestal pressure. The effect of TF ripple on pedestal characteristics at lower collisionality close to ITER should be investigated as a next step study.

Deuterium retention in porous vacuum plasma-sprayed tungsten coating exposed to low-energy, high-flux pure and helium-seeded D plasma

Alimov, V.; Tyburska, B.*; Ogorodnikova, O. V.*; Roth, J.*; Isobe, Kanetsugu; Yamanishi, Toshihiko

Journal of Nuclear Materials, 415(Suppl.1), p.S628 - S631, 2011/08

https://doi.org/10.1016/j.jnucmat.2010.08.054

Deuterium retention in porous vacuum plasma spraying tungsten coating exposed at various temperatures to a low-energy, high flux (10 D/ms) pure D and helium-seeded D plasmas was examined by thermal desorption spectroscopy and the nuclear reaction. Under exposure to pure D plasma (76 eV D) at 340-560 K, the D concentration reaches 12 at.% at depths of several micrometers, while at temperatures above 700 K the D concentration is below 10 at.% and deuterium is retained over the whole thickness of the coating. Seeding of 76 eV He into the D plasma reduces the D retention at temperatures of 400-600 K. However, at temperature above 700 K, the D retention becomes comparable to that for pure D plasma exposure.

Effect of AlO nanoparticles on radiolytic HO production in water

Roth, O.*; Hiroki, Akihiro; LaVerne, J. A.*

Journal of Physical Chemistry C, 115(16), p.8144 - 8149, 2011/04

https://doi.org/10.1021/jp111918v

Hydrogen peroxide, HO, is the major stable oxidizing species produced in the radiolysis of water and understanding the mechanisms involved in its production is important both from a fundamental science perspective and for engineering purposes, in particular within the nuclear power industry. In this work, the yields of HO were determined in aqueous slurries in the pH range of 1-13 with various amounts of added AlO nanoparticles. The addition of AlO generally decreased HO yields at all pH values within this range in the radiolysis of both deaerated and aerated slurries, except at very high pH. Very little effect of pH was observed in the radiolysis of deaerated systems in the pH range of 3-8, whereas a large increase in HO yields was observed in aerated AlO slurries at the extreme pH values. Scavenger capacity studies using methanol as an OH radical scavenger show that the decrease in HO yields with added AlO occurs at relatively long time scales and is probably due to reaction of the solid nanoparticles with OH radicals.

Current ramps in tokamaks; From present experiments to ITER scenarios

Imbeaux, F.*; Basiuk, V.*; Budny, R.*; Casper, T.*; Citrin, J.*; Fereira, J.*; Fukuyama, Atsushi*; Garcia, J.*; Gribov, Y. V.*; Hayashi, Nobuhiko; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2010/10

http://www-naweb.iaea.org/napc/physics/FEC/FEC2010/html/node62.htm#15641

In order to prepare adequate current ramp-up and ramp-down scenarios for ITER, present experiments from several tokamaks have been analyzed by means of integrated modeling in view of determining relevant heat transport models for these operation phases. The results of these studies are presented and projections to ITER current ramp-up and ramp-down scenarios are done, focusing on the baseline inductive scenario (main heating plateau current of 15 MA). Various transport models have been tested by means of integrated modeling against experimental data from ASDEX Upgrade, C-Mod, DIII-D, JET and Tore Supra, including both Ohmic plasmas and discharges with additional heating/current drive. With using the most successful models, projections to the ITER current ramp-up and ramp-down phases are carried out. Though significant differences between models appear on the electron temperature prediction, the final q-profiles reached in the simulation are rather close.

Beam collimation and transport of quasineutral laser-accelerated protons by a solenoid field

Harres, K.*; Alber, I.*; Tauschwitz, A.*; Bagnoud, V.*; Daido, Hiroyuki; Gnther, M.*; Nrnberg, F.*; Otten, A.*; Schollmeier, M.*; Schtrumpf, J.*; et al.

Physics of Plasmas, 17(2), p.023107_1 - 023107_7, 2010/02

https://doi.org/10.1063/1.3299391

Proton acceleration experiments and warm dense matter research using high power lasers

Roth, M.*; Alber, I.*; Bagnoud, V.*; Brown, C. R. D.*; Clarke, R.*; Daido, Hiroyuki; Fernandez, J.*; Flippo, K.*; Gaillard, S.*; Gauthier, C.*; et al.

Plasma Physics and Controlled Fusion, 51(12), p.124039_1 - 124039_7, 2009/12

https://doi.org/10.1088/0741-3335/51/12/124039

Effects of ferromagnetic components on energetic ion confinement in ITER

Shinohara, Koji; Oikawa, Toshihiro; Urano, Hajime; Oyama, Naoyuki; Lnnroth, J.*; Saibene, G.*; Parail, V.*; Kamada, Yutaka

Fusion Engineering and Design, 84(1), p.24 - 32, 2009/01

https://doi.org/10.1016/j.fusengdes.2008.08.040

Pedestal stability comparison and ITER pedestal prediction

Snyder, P. B.*; Aiba, Nobuyuki; Beurskens, M.*; Groebner, R. J.*; Horton, L. D.*; Hubbard, A. E.*; Hughes, J. W.*; Huysmans, G. T. A.*; Kamada, Yutaka; Kirk, A.*; et al.

Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 8 Pages, 2008/10

Investigation of intermediate wavelength MHD modes has led to improved understanding of important constraints on the pedestal height and the mechanism for ELMs. The combination of high resolution pedestal diagnostics and a suite of highly efficient stability codes, has made edge stability analysis routine on several major tokamaks, contributing both to understanding, and to experimental planning and performance optimization. Here we present extensive comparisons of observations to predicted edge stability boundaries on several tokamaks, both for the standard ELM regime, and for small ELM and ELM-free regimes. We further use the stability constraint on pedestal height to test models of the pedestal width, and self-consistently combine a simple width model with MHD stability calculations to develop a new predictive model (EPED1) for the pedestal height and width. This model is tested against experimental measurements, and used in initial predictions of the pedestal height for ITER.