Search results for "asma"

Spotlighting phase separation in Rashba spin-orbit coupled Bose–Einstein condensates in two dimensions

2018

The Influence of a Magnetized Plasma Column on the Radiation Characteristics of a Strip Loop Antenna

2014

The radiation characteristics of a circular loop antenna located on the surface of an open waveguide in the form of an axially magnetized plasma column are studied using the rigorously obtained current distribution of such an antenna. The radiation resistance of the antenna excited by a time-harmonic external voltage is obtained for the case where the plasma inside the column is resonant. The distribution of the radiated power over the spatial spectrum of the excited waves is found and discussed.

Widespread Nanoflare Variability Detected with Hinode/X-Ray Telescope in a Solar Active Region

2011

It is generally agreed that small impulsive energy bursts called nanoflares are responsible for at least some of the Sun's hot corona, but whether they are the explanation for most of the multimillion-degree plasma has been a matter of ongoing debate. We present here evidence that nanoflares are widespread in an active region observed by the X-Ray Telescope on board the Hinode mission. The distributions of intensity fluctuations have small but important asymmetries, whether taken from individual pixels, multipixel subregions, or the entire active region. Negative fluctuations (corresponding to reduced intensity) are greater in number but weaker in amplitude, so that the median fluctuation i…

Simulation of matrix product states for dissipation and thermalization dynamics of open quantum systems

2020

Abstract We transform the system/reservoir coupling model into a one-dimensional semi-infinite discrete chain through unitary transformation to simulate the open quantum system numerically with the help of time evolving block decimation (TEBD) algorithm. We apply the method to study the dynamics of dissipative systems. We also generate the thermal state of a multimode bath using minimally entangled typical thermal state (METTS) algorithm, and investigate the impact of the thermal bath on an empty system. For both cases, we give an extensive analysis of the impact of the modeling and simulation parameters, and compare the numerics with the analytics.

Analyse statistique de la phase des solitons optiques

2005

On analyse numeriquement la statistique de la phase des solitons optiques et on arrive a determiner la fonction de densite de probabilite. Nos resultats sont en accord avec les theories existantes, qui sont basees sur les proprietes des solitons.

Coupled fluid-flow and magnetic-field simulation of the Riga dynamo experiment

2006

Magnetic fields of planets, stars, and galaxies result from self-excitation in moving electroconducting fluids, also known as the dynamo effect. This phenomenon was recently experimentally confirmed in the Riga dynamo experiment [ A. Gailitis et al., Phys. Rev. Lett. 84, 4365 (2000) ; A. Gailitis et al., Physics of Plasmas 11, 2838 (2004) ], consisting of a helical motion of sodium in a long pipe followed by a straight backflow in a surrounding annular passage, which provided adequate conditions for magnetic-field self-excitation. In this paper, a first attempt to simulate computationally the Riga experiment is reported. The velocity and turbulence fields are modeled by a finite-volume Navi…

Spectroscopie Raman Anti-Stokes Cohérente femtoseconde (DRASC – fs) : expériences et modélisation dans le cas du mélange H2 – N2 à basse pression

2006

Dans l'objectif du diagnostic de la temperature dans les milieux en combustion, la Diffusion Raman Anti-Stokes Coherente resolue en temps (DRASC - fs) est utilisee pour sonder H 2 dans les melanges H 2 -N 2 a basse pression. Le dispositif DRASC mis en place est decrit en detail. Un nouveau modele de la reponse DRASC temporelle, prenant en compte tous les effets collisionnels specifiques a l'hydrogene (effets dits « de vitesse ») est presentee, ainsi que la comparaison avec l'experience, l'accord se revelant tres satisfaisant.

On the existence of kinetic equations

1974

The existence of the Boltzmann equation and its generalizations is studied by analysing the order of magnitude of their terms. As a consequence we conclude that the reduced distribution functions are not analytic in the density.

Total absorption studies of high priority decays for reactor applications: 86Br and 91Rb

2017

Preliminary results from beta decay studies of nuclei that are important for reactor applications are presented. The beta decays have been studied using the total absorption technique (TAS) and the pure beams provided by the JYFLTRAP system at the IGISOL facility of the University of Jyväskylä. peerReviewed

Strong-field-ionization suppression by light-field control

2012

In recent attempts to control strong-field phenomena such as molecular dissociation, undesired ionization sometimes seriously limited the outcome. In this work we examine the capability of quantum optimal control theory to suppress the ionization by rational pulse shaping. Using a simple model system and the ground-state occupation as the target functional, we show that optimal control generally leads to a significant suppression of the ionization, although the fluence and the pulse length are kept fixed. In the low-frequency regime the ionization is reduced mainly by avoiding high peaks in the intensity and thus preventing tunneling. In contrast, at high frequencies in the extreme ultravio…