A5067570101- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Geomagnetism and Paleomagnetism Studies
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fluid Dynamics and Turbulent Flows
- Computational Fluid Dynamics and Aerodynamics
- Astrophysics and Cosmic Phenomena
- Laser-Plasma Interactions and Diagnostics
- Magnetic and Electromagnetic Effects
- Characterization and Applications of Magnetic Nanoparticles
- Plasma and Flow Control in Aerodynamics
- Geophysics and Gravity Measurements
- Advanced Data Storage Technologies
- Phase Equilibria and Thermodynamics
- Aerodynamics and Acoustics in Jet Flows
- Research Data Management Practices
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Plant Surface Properties and Treatments
- Space Exploration and Technology
King Abdullah University of Science and Technology
2015-2017
European Science Foundation
2007-2011
Dublin Institute For Advanced Studies
2000-2007
Laboratoire Univers et Théories
2004
Université de Montpellier
2002
Queen's University
1999-2000
Queens University
1999
We present the first results of high energy density laboratory astrophysics experiments which explore evolution collimated outflows and jets driven by a toroidal magnetic field. The are scalable to astrophysical flows in that critical dimensionless numbers such as Mach number, plasma β Reynolds number all astrophysically appropriate ranges. Our use MAGPIE pulsed power machine allow us role pressure creating collimating outflow well showing creation central jet within broader cavity. show...
The evolution of laboratory produced magnetic jets is followed numerically through three-dimensional, nonideal magnetohydrodynamic simulations. experiments are designed to study the interaction a purely toroidal field with an extended plasma background medium. system observed evolve into structure consisting approximately cylindrical cavity embedded magnetically confined jet on its axis. supersonic expansion produces shell swept-up shocked that surrounds and partially confines tower....
Radiative shock waves are observed around astronomical objects in a wide variety of environments, for example, they herald the birth stars and sometimes their death. Such shocks can also be created laboratory, by using energetic lasers. In case, each observation is unique almost fixed time, while produced laboratory numerical simulations reproduced, investigated greater detail. The combined study experimental computational results, as presented here, becomes powerful probe to understanding...
MHD jet equilibria that depend on source properties are obtained using a simplified model for stationary, axisymmetric and rotating magnetized outflows (Lery et al.). The present rotation laws more complex than previously considered include Keplerian disc. ensuing jets have dense, current-carrying central core surrounded by an outer collar with return current. intermediate part of the is almost current-free magnetically dominated. Most momentum located around axis in dense core, this region...
We present simulations of the propagation magnetized jets. This work differs from previous studies in that cross-sectional distributions jets's state variables are derived analytical models for magneto-centrifugal launching. The source is a rotator whose properties specfied as boundary conditions. jets these considerably more complex than ``top-hat''constant density etc. profiles used work. find and magnetic field stratification (with radius) jet leads to new behavior including separation an...
Powerful, highly collimated jets, surrounded by bipolar molecular outflows, are commonly observed near Young Stellar Objects (YSOs). In the usual theoretical picture of star formation, a jet is ejected from magnetized accretion disk, with outflow being driven either or wider wind coming disk. Here, we propose an alternative global model for flows surrounding YSOs. addition to central accretion-ejection engine driving jet, powered infalling matter and follows circulation pattern around object...
<ns4:p>Quantitative data are crucial in the assessment of research impact academic world. However, as a young university created 2009, King Abdullah University Science and Technology (KAUST) needs to aggregate bibliometrics from researchers coming diverse origins, not necessarily with proper affiliations. In this context, has launched an institutional repository September 2012 objectives creating home for intellectual outputs KAUST researchers. Later, adopted first mandated open access...
We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and However, binary jets have only been observed in a very small number of systems. model numerically 3D for various outflow parameters. also the propagation from specific source, namely L1551 IRS 5, known to two jets, using recent observations as constraints simulations with new MHD code. examine...
We address the issue of ambipolar diffusion in Herbig-Haro (HH) jets. The current consensus holds that these jets are launched and collimated via MHD forces. Observations have, however, shown can be mildly to weakly ionized. Beginning with a simple model for cylindrical equilibrium between neutral, plasma, magnetic pressures, we calculate characteristic timescale diffusion. Our results show significant fraction HH will have timescales equivalent to, or less than, dynamical timescales. This...
The formation and collapse of a protostar involves the simultaneous infall outflow material in presence magnetic fields, self-gravity rotation. We use self-similar techniques to self-consistently model anisotropic by using set angle-separated equations. is quite strong our model, with velocity increasing proportion radius, formally escaping infinity finite time required for central singularity develop. Analytically tractable models have been limited mainly spherically symmetric collapse,...
The integration of research information systems with existing university processes has tended towards exchange models in which the CRIS ingests from and takes on functions that were previously distributed across several independent solutions. This paper draws upon experience implementation a at King Abdullah University Science Technology (KAUST) to posit model remain so as take advantage strengths each system. discussed include institutional reporting, publications tracking, preservation...
A simplified model for the stationary, axisymmetric structure of magnetized winds with a polytropic equation state is presented. The shape magnetic surfaces assumed to be known (conical in this paper) within fast magnetosonic surface. non-self-similar. regularity at critical ensured by Alfv\`en condition and criticality conditions slow points. These are used evaluate three constants motion, total energy, angular momentum, ratio mass flux $\alpha$, as well surfaces. rotation rate $\Omega$...
In this work, the gas infall and formation of outflows around low high mass protostars are investigated. A radial self-similar approach to model transit molecular central object is employed. We include gravitational radiative fields produce heated pressure-driven with magneto-centrifugal acceleration collimation. Outflow solutions negligible or vanishing magnetic field reported. They indicate that thermodynamics a sufficient engine generate an outflow. The magnetized show dynamically...
The present article addresses the problem of formation both low and high mass stars. We suggest how competing factors change behaviours proto‐stellar sources outflows in cases. also describe a possible temporal sequence for flows around protostar, that may help to give physical justification empirical classification pre‐main sources.
The asymptotic structure of outflows from rotating magnetized objects confined by a uniform external pressure is calculated. flow assumed to be perfect MHD, polytropic, axisymmetric and stationary. well known associated first integrals together with the confining pressure, which taken independent distance source, determine structure. are provided solving physics for base within framework model developed in Paper I (Lery et al. 1998), assumes conical geometry below fast mode surface, ensures...
We discuss the propagation of radiative MHD jets and outflows focusing on driven by magneto-centrifugal rotators. Our goal is to link properties with physics sources which produce them. find that density magnetic field stratification (with radius) in from magnetized rotators leads new behavior including development a dense inner jet core low collar. also report more general studies ambipolar diffusion geometry pulsed jets. Finally we describe work designed study effects winds circumstellar...