Transverse expansion of hot magnetized Bjorken flow in heavy ion collisions

We argue that the existence of an inhomogeneous external magnetic field can lead to radial flow in transverse plane. Our aim is to show how the introduction of a magnetic field generalizes the Bjorken flow. We investigate the effect of an inhomogeneous weak external magnetic field on the transverse expansion of in-viscid fluid created in high energy nuclear collisions. In order to simplify our calculation and compare with Gubser model, we consider the fluid under investigation to be produced in central collisions, at small impact parameter; azimuthal symmetry has been considered. In our model, we assume an inhomogeneous external magnetic field following the power-law decay in proper time and having radial inhomogeneity perpendicular to the radial velocity of the in-viscid fluid in the transverse plane; then the space time evolution of the transverse expansion of the fluid is obtained. We also show how the existence of an inhomogeneous external magnetic field modifies the energy density. Finally we use the solutions for the transverse velocity and energy density in the presence of a weak magnetic field, to estimate the transverse momentum spectrum of protons and pions emerging from the Magneto-hydrodynamic solutions

Non-relativistic approximate numerical ideal-magneto hydrodynamics of (1+1) D transverse flow in Bjorken scenario

In this study, we investigate the impact of the magnetic field on the evolution of the transverse flow of QGP matter in the magneto-hydrodynamic (MHD) framework. We assume that the magnetic field is perpendicular to the reaction plane and then we solve the coupled Maxwell and conservation equations in (1+1D) transverse flow, within the Bjorken scenario. We consider a QGP with infinite electrical conductivity. First, the magnetic effects on the QGP medium at mid-rapidity are investigated at leading order; then the time and space dependence of the energy density, velocity and magnetic field in the transverse plane of the ideal magnetized hot plasma are obtained

Simulation of axial channeling radiation on a thin Ge single crystal

Based on classical electrodynamics the radiation emitted by axially channeled electrons has been investigated by means of computer simulations. Using the Doyle-Turner approximation for the atomic scattering factor and taking thermal vibrations of atoms into account, we calculated the two-dimensional continuum potential of the 110 crystallographic axis of a thin Ge single crystal. The trajectories, velocities and accelerations of electrons are obtained by solving the equations of motion in three dimensions, and the spectral-angular distribution of radiation has been calculated within classical approach

Transverse and non-boost longitudinal expansion of (2+1)dimensional relativistic ideal-hydrodynamics flow in heavy ion collisions

This study investigates the evolution of quark gluon plasma (QGP) within a generalized Bjorken flow framework. The medium under consideration is assumed to possess a finite transverse size and to expand both radially and along the beam axis. However, we assume that the boost invariance of longitudinal expansion is broken. To be more specific, we generalize the Bjorken solution to include the acceleration and transverse expansion of the fluid. We analytically study the (2 + 1) dimensional longitudinal acceleration expansion of hot and dense quark matter, applying a perturbation approach to solve the relativistic hydrodynamics equations. This procedure enables us to obtain exact algebraic expressions for fluid velocities and energy densities in both transverse and longitudinal directions. To simplify our calculations, we assume that the fluid is produced in central collisions, and therefore, we consider azimuthal symmetry. We compare the radial velocity and correction energy density with those obtained from the Gubser model. Furthermore, we determine the fluid's acceleration parameter and longitudinal correction energy density, which exhibits a Gaussian distribution

Channeling radiation on quartz stimulated by acoustic waves

The stimulation of channeling radiation by acoustic waves excited in the single crystal has been predicted in early works of the 1980’s. Based on quantum calculations, the described experiment aimed at verification of theoretical considerations. Making use of the reverse piezoelectric effect, hypersonic waves of frequency 12GHz, which corresponds to a dedicated transition between bound states of planar channelled relativistic electrons, were excited in a single-Crystal quartz plate. The spectrum of channeling radiation measured under the influence of acoustic waves reveals enhanced radiation intensity. The obtained results are discussed and may be phenomenologically understood assuming electron diffraction on an acoustic superlattice

Future aspects of X-ray emission from crystal undulators at channeling of positrons

In connection with ideas to produce undulator-like radiation in the hundreds of keV up to the MeV region by means of positron and electron channeling, there is renewed interest to study various channeling phenomena also experimentally. With electrons experiments have been performed at the Mainz Microtron MAMI to explore channeling-radiation emission by a 4-period epitaxially grown strained layer Si1−xGex undulator with a period length of λu = 9.9 μm. Unfortunately, high-quality positron beams of sufficient intensity are not easily accessible. The only serious candidate in Europe seems to be the Beam Test Facility (BTF) at INFN/LNF, Frascati, Italy. Some requirements to extent BTF in a facility which is also well suited for positron channeling-radiation experiments will be outlined

Towards a taxonomy of process quality characteristics for assessment

Previous assessment of process quality have focused on process capability (i.e. the ability of a process to meet its stated goals). This paper proposes a taxonomy of alternative process quality characteristics based on intrinsic and extrinsic quality attributes. The ultimate goal of this taxonomy is to provide a framework to conduct process assessments using different process quality aspects. Such a framework would considerably broaden process quality perspectives beyond the primary measure of process capability. It would also allow practitioners to identify and evaluate relevant quality characteristics for processes based on specific contexts and implications. For the process assessment model developers, it offers a list of process quality characteristics that could be used to develop relevant process measurement frameworks

The serious games ecosystem: Interdisciplinary and intercontextual praxis

This chapter will situate academia in relation to serious games commercial production and contextual adoption, and vice-versa. As a researcher it is critical to recognize that academic research of serious games does not occur in a vaccum. Direct partnerships between universities and commercial organizations are increasingly common, as well as between research institutes and the contexts that their serious games are deployed in. Commercial production of serious games and their increased adoption in non-commercial contexts will influence academic research through emerging impact pathways and funding opportunities. Adding further complexity is the emergence of commercial organizations that undertake their own research, and research institutes that have inhouse commercial arms. To conclude, we explore how these issues affect the individual researcher, and offer considerations for future academic and industry serious games projects