Results 241 to 250 of about 189,025 (287)

Intrinsic Localized Anharmonic Modes at Crystal Edges

Physical Review Letters, 1995
Using a realistic lattice-dynamical model for a diatomic crystal, time-periodic anharmonic vibrations have been found with displacement pattern localized at an edge of the crystal. The localization is not only in the direction normal, but also in the directions parallel to the edge along which the lattice is periodic.
, Bonart, , Mayer, , Schröder
openaire   +2 more sources

Model for Current-Driven Edge-Localized Modes

Physical Review Letters, 2006
Edge-localized modes (ELMs) are cyclic disturbances in the outer region of tokamak plasmas that are influential in determining present and future tokamak performance. In this Letter, we outline an approach to modeling ELMs in which we envisage toroidal peeling modes initiating a Taylor relaxation [Phys. Rev. Lett.
C G, Gimblett, R J, Hastie, P, Helander
openaire   +2 more sources

Spatial and Temporal Structure of Edge-Localized Modes

Physical Review Letters, 2004
This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), and highlights similarities with solar eruptions. Taken together, the observations presented in this Letter provide strong evidence for ELMs being associated with a
Kirk, A., Wilson, H.R., Counsell, G.F., Akers, R., Arends, E., Cowley, S.C., Dowling, J., Lloyd, B., Price, M., Walsh, M.   +9 more
openaire   +2 more sources

Edge-localized modes and edge transport in spherical tokamaks

Physics of Plasmas, 2005
Turbulent energy transport in numerical simulations of the edge region of spherical tokamaks with small toroidal aspect ratio A=1.5 is directly compared to that in conventional tokamaks with larger aspect ratio A=3. Depending upon the aspect ratio of the torus, the energy flux can vary greatly.
Robert G. Kleva, Parvez N. Guzdar
openaire   +1 more source

Magnetohydrodynamic activity during edge localized modes on ASDEX

Nuclear Fusion, 1990
Magnetohydrodynamic (MHD) activity during edge localized modes (ELMs) has been monitored in the ASDEX tokamak. Besides a fast inward shift of the plasma column, a helical MHD perturbation has been found to accompany ELMs. For the discharges investigated, the helical instability has a poloidal mode number m of 3 or 4 and a toroidal mode number n of 1 ...
Von Goeler, S., Klueber, O., Fussmann, G., Gernhardt, J., Kornherr, M.   +4 more
openaire   +2 more sources

Edge localized modes (ELMs)

Plasma Physics and Controlled Fusion, 1996
The phenomenology of edge localized modes (ELMs), an MHD instability occurring in the edge of H-mode plasmas in toroidal magnetic fusion experiments, is described. ELMs are important to obtain experimental control of the particle inventory of fusion plasmas.
openaire   +3 more sources

Edge localized modes control: experiment and theory

Journal of Nuclear Materials, 2005
The paper reviews recent theoretical and experimental results focussing on the identification of the key factors controlling ELM energy and particle losses both in natural ELMs and in the presence of external controlling mechanisms. Present experiment and theory pointed out the benefit of the high plasma shaping, high q(95) and high pedestal density in
Becoulet, M., Huysmans, G., Thomas, P., Joffrin, E., Rimini, F., Monier-Garbet, P., Grosman, A., Ghendrih, P., Parail, V., Lomas, P., Matthews, G., Wilson, H., Gryaznevich, M., Counsell, G., Loarte, A., Saibene, G., Sartori, R., Leonard, A., Snyder, P., Evans, T., Moyer, R., Gohil, P., Moyer, R., Kamada, Y., Oyama, N., Hatae, T., Kamiya, K., Degeling, A., Martin, Y., Lister, J., Rapp, J., Perez, C., Lang, P., Chankin, A., Eich, T., Sips, A., Stober, J., Horton, L., Kallenbach, A., Suttrop, W., Saarelma, S., Cowley, S., Lönnroth, J., Shimada, M., Polevoi, A., Federici, G.   +45 more
openaire   +3 more sources

Edge Localized Modes in Tokamaks

Fusion Science and Technology, 2012
As one increases the heating power in a tokamak beyond a threshold, the confinement undergoes a bifurcation, with a dramatic increase in the confinement time by a factor ~2.
openaire   +1 more source

Insights into type‐I edge localized modes and edge localized mode control from JOREK non‐linear magneto‐hydrodynamic simulations

Contributions to Plasma Physics, 2018
Edge localized modes (ELMs) are repetitive instabilities driven by the large pressure gradients and current densities in the edge of H‐mode plasmas. Type‐I ELMs lead to a fast collapse of the H‐mode pedestal within several hundred microseconds to a few milliseconds.
Hoelzl, M., Huijsmans, G.T. A., Orain, F., Artola, F.J., Pamela, S., Becoulet, M., van Vugt, D., Liu, F., Futatani, S., Vanovac, B., Lessig, A., Wolfrum, E., Mink, F., Trier, E., Dunne, M., Viezzer, E., Eich, T., Frassinetti, L., Gunter, S., Lackner, K., Krebs, I., Team, ASDEXUpgrade, EUROfusion MST1 Team,   +22 more
openaire   +3 more sources

Studies of edge localized modes on ASDEX

Nuclear Fusion, 1992
The MHD behaviour connected with edge localized modes (ELMs) is studied using fast sample rate fluctuation diagnostics. It is found that ELMs on ASDEX are generally preceded by a coherent MHD mode of medium poloidal mode number (m=10-15). At the onset of the ELM the mode behaviour changes to a turbulent one, leading to an outflux of heat and particles.
Zohm, Hartmut, Wagner, F., Endler, M., Gernhardt, J., Holzhauer, E., Kerner, W., Mertens, V.   +6 more
openaire   +2 more sources