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Microscale turbulence drives not only particle and heat transport but also energy exchange between different particle species. Previous local gyrokinetic studies have shown that turbulent energy exchange can exceed collisional exchange in…

Plasma Physics · Physics 2026-02-10 T. Kato , H. Sugama , M. Honda

We theoretically study the atomic structure and energetics of silicon and silicon-nitrogen impurities in graphene. Using density-functional theory, we get insight into the atomic structures of the impurities, evaluate their formation…

Mesoscale and Nanoscale Physics · Physics 2016-01-20 Mikko M. Ervasti , Zheyong Fan , Andreas Uppstu , Arkady Krasheninnikov , Ari Harju

Results from a database analysis of H-mode electron density profiles on the Tokamak \`a Configuration Variable (TCV) in stationary conditions show that the logarithmic electron density gradient increases with collisionality. By contrast,…

Plasma Physics · Physics 2012-07-10 Dávid Wágner , Emiliano Fable , Andreas Pitzschke , Olivier Sauter , Henri Weisen

The linear gyrokinetic stability properties of magnetically confined electron-positron plasmas are investigated in the parameter regime most likely to be relevant for the first laboratory experiments involving such plasmas, where the…

Plasma Physics · Physics 2016-06-16 Per Helander , J. W. Connor

In Hybrid plasma operation in JET with its ITER-like wall (JET-ILW) it is found that n>1 tearing activity can significantly enhance the rate of on-axis peaking of tungsten impurities, which in turn significantly degrades discharge…

A dimensionless collisionality scan has been performed in H-mode plasmas on DIII-D tokamak, with detailed measurements of intermediate-to-high wavenumber turbulence using Doppler backscattering systems. It is found that the shorter…

Plasma Physics · Physics 2023-08-17 R. Hong , T. L. Rhodes , Y. Ren , P. H. Diamond , X. Jian , L. Zeng , K. Barada , Z. Yan , G. R. McKee

Turbulent transport is a decisive factor in determining the pedestal structure of H-modes. Here, we present the first comprehensive characterization of gyrokinetic turbulent transport in a JET hybrid H-mode pedestal. Local, linear…

Plasma Physics · Physics 2024-05-20 L. A. Leppin , T. Görler , L. Frassinetti , S. Saarelma , J. Hobirk , F. Jenko , JET contributors

The effects of the electron inertia on the current sheets that are formed out of kinetic turbulence are relevant to understand the importance of coherent structures in turbulence and the nature of turbulence at the dissipation scales. We…

The gyrokinetic stability of electron-positron plasmas contaminated by ion (proton) admixture is studied in slab geometry. The appropriate dispersion relation is derived and solved. The ion-temperature-gradient driven instability, the…

Plasma Physics · Physics 2018-03-14 Alexey Mishchenko , Alessandro Zocco , Per Helander , Axel Koenies

Many cuprate superconductors possess an unusual charge-ordered phase that is characterized by an approximate $d_{x^2-y^2}$ intra-unit cell form factor and a finite modulation wavevector $\bq^\ast$. We study the effects impurities on this…

Superconductivity · Physics 2015-07-16 W. A. Atkinson , A. P. Kampf

Impurities coupled to superconductors offer a controlled platform to understand the interplay between superconductivity, many-body interactions, and non-equilibrium physics. In the equilibrium situation, local interactions at the impurity…

Mesoscale and Nanoscale Physics · Physics 2021-12-17 R. Seoane Souto , A. E. Feiguin , A. Martín-Rodero , A. Levy Yeyati

We present a numerical study of collisional transport in a tokamak pedestal in the presence of non-trace impurities, using the radially global $\delta f$ neoclassical solver PERFECT [M. Landreman et al. 2014 Plasma Phys. Control. Fusion 56…

Plasma Physics · Physics 2016-08-03 I. Pusztai , S. Buller , M. Landreman

We explore polaronic quantum transport in three-dimensional models of disordered organic crystals with strong coupling between electronic and vibrational degrees of freedom. By studying the polaron dynamics in a static disorder environment,…

Materials Science · Physics 2015-06-03 Frank Ortmann , Stephan Roche

Motivated by recent advances in fabricating graphene nanostructures, we find that an electron can be trapped in Z-shaped graphene nanoconstriction with zigzag edges. The central section of the constriction operates as a single-level quantum…

Mesoscale and Nanoscale Physics · Physics 2010-09-23 Adam Rycerz

The impurity concentration dependence of superconducting transition temperature $T_c$ is studied within the framework of two band model of order parameter anisotropy. Both intraband and interband electron scattering by nonmagnetic and…

Superconductivity · Physics 2007-05-23 P. I. Arseev , N. K. Fedorov , S. O. Loiko

An accurate description of turbulence up to the transport time scale is essential for predicting core plasma profiles and enabling reliable calculations for designing advanced scenarios and future devices. Here, we exploit the gap…

It has been observed that impurity doping and/or ion-beam-induced damage in high $T_{c}$ superconductors cause a metal-insulator transition and thereby suppress the critical temperature. Based on our recent theory of the weak localization…

Superconductivity · Physics 2016-08-31 Yong-Jihn Kim , K. J. Chang

We consider electronic spectra of twisted carbon nanotubes and their perturbation by impurity atoms absorbed at different positions on nanotube surface within the framework of Anderson hybrid model. A special attention is given to the cases…

Mesoscale and Nanoscale Physics · Physics 2025-05-21 Yuriy G. Pogorelov , Volodymyr Turkowski , Vadim M. Loktev

It is shown on the basis of the Fermi liquid theory that the s-wave scattering potential due to nonmagnetic impurity is strongly enhanced by the mass enhancement factor $1/z$. As a result the impurity potential with moderate strength, of…

Condensed Matter · Physics 2007-05-23 Hiroaki Ikeda , Kazumasa Miyake

We explore the dynamical transport of an impurity between different embedding majority species which are spatially separated in a double well. The transfer and storage of the impurity is triggered by dynamically changing the interaction…

Quantum Gases · Physics 2022-11-30 Judith Becker , Maxim Pyzh , Peter Schmelcher