Alberto Bottino

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A global plasma turbulence simulation code, ORB5, is presented. It solves the gyrokinetic electrostatic equations including zonal flows in axisymmetric magnetic geometry. The present version of the code assumes a Boltzmann electron response on magnetic surfaces. It uses a Particle-In-Cell (PIC), δf scheme, 3D cubic B-splines finite elements for the field(More)
This contribution presents theoretical results on the transport of light and heavy impurities, as well as of energetic α particles, produced by the background electrostatic plasma turbulence. Linear and nonlinear simulations with three gyrokinetic codes, GS2, GYRO, and the recently developed GKW, are performed in concert with analytical derivations, in(More)
The aim of this study was to test the relationships between jump squat (JS) and Olympic push press (OPP) power outputs and performance in sprint, squat jump (SJ), countermovement jump (CMJ) and change of direction (COD) speed tests in elite soccer players. 27 athletes performed a maximum power load test to determine their bar mean propulsive power (MPP) and(More)
Improved electron energy confinement in tokamak plasmas, related to internal transport barriers, has been linked to nonmonotonic current density profiles. This is difficult to prove experimentally since usually the current profiles evolve continuously and current injection generally requires significant input power. New experiments are presented, in which(More)
microturbulence simulations T. Vernay, S. Brunner, L. Villard, B. F. McMillan, S. Jolliet, T. M. Tran, A. Bottino, and J. P. Graves Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Association EURATOM–Confédération Suisse, CH-1015 Lausanne, Switzerland Japan Atomic Energy Agency, Higashi-Ueno 6-9-3, Taitou, Tokyo(More)
In this work, a Fourier solver [McMillan et. al., Comput. Phys. Commun. 181, 715 (2010)] is implemented in the global Eulerian gyrokinetic code GT5D [Y. Idomura et. al., Nucl. Fusion 49, 065029, 2009] and in the global Particle-In-Cell code ORB5 [S. Jolliet et. al., Comput. Phys. Commun 177, 477 (2007)] in order to reduce the memory of the matrix associated(More)
The theoretical study of plasma turbulence is of central importance to fusion research. Experimental evidence indicates that the confinement time results mainly from the turbulent transport of energy, the magnitude of which depends on the turbulent state resulting from nonlinear saturation mechanisms, in particular, the self-generation of coherent(More)
Critical physical issues can be specifically tackled with the global full-f gyrokinetic code GYSELA. Three main results are presented. First, the selfconsistent treatment of equilibrium and fluctuations highlights the competition between two compensation mechanisms for the curvature driven vertical charge separation, namely, parallel flow and polarization.(More)
The scaling of turbulence-driven heat transport with system size in magnetically confined plasmas is reexamined using first-principles based numerical simulations. Two very different numerical methods are applied to this problem, in order to resolve a long-standing quantitative disagreement, which may have arisen due to inconsistencies in the geometrical(More)
In the frame of an effective MSSM model without gaugino-mass unification at a grand unification scale, we set a lower bound on the neutralino mass based on the new WMAP data on ΩCDM (R-parity conservation is assumed). Our lower bound, mχ > ∼ 6 GeV, leaves much room for relic neutralinos significantly lighter than those commonly considered (mχ > ∼ 50 GeV).(More)