Resource Type

Month

Interference effect in elastic parton energy loss in a finitemedium (open access)

Interference effect in elastic parton energy loss in a finitemedium

Similar to the radiative parton energy loss due to gluonbremsstrahlung, elastic energy loss of a parton undergoing multiplescattering in a finite medium is demonstrated to be sensitive tointerference effect. The interference between amplitudes of elasticscattering via a gluon exchange and that of gluon radiation reduces theeffective elastic energy loss in a finite medium and gives rise to anon-trivial length dependence. The reduction is most significant for apropagation length L<4/\pi T in a medium with a temperature T. Thoughthe finite size effect is not significant for the average partonpropagation in the most central heavy-ion collisions, it will affect thecentrality dependence of its effect on jet quenching.
Date: April 18, 2005
Creator: Wang, Xin-Nian
System: The UNT Digital Library
Radiation-driven hydrodynamics of high-Z hohlraums on the National Ignition Facility (open access)

Radiation-driven hydrodynamics of high-Z hohlraums on the National Ignition Facility

None
Date: April 18, 2005
Creator: Dewald, E. L.; Suter, L. J.; Landen, O. L.; Thomas, B. R.; Holder, J. P.; Lee, F. D. et al.
System: The UNT Digital Library
Spectroscopy of Argon Excited in an Electron Beam Ion Trap (open access)

Spectroscopy of Argon Excited in an Electron Beam Ion Trap

Argon is one of the gases best investigated and most widely used in plasma discharge devices for a multitude of applications that range from wavelength reference standards to controlled fusion experiments. Reviewing atomic physics and spectroscopic problems in various ionization stages of Ar, the past use and future options of employing an electron beam ion trap (EBIT) for better and more complete Ar data in the x-ray, EUV and visible spectral ranges are discussed.
Date: April 18, 2005
Creator: Trabert, E
System: The UNT Digital Library
Iterative Schemes for Time Parallelization with Application to Reservoir Simulation (open access)

Iterative Schemes for Time Parallelization with Application to Reservoir Simulation

Parallel methods are usually not applied to the time domain because of the inherit sequentialness of time evolution. But for many evolutionary problems, computer simulation can benefit substantially from time parallelization methods. In this paper, they present several such algorithms that actually exploit the sequential nature of time evolution through a predictor-corrector procedure. This sequentialness ensures convergence of a parallel predictor-corrector scheme within a fixed number of iterations. The performance of these novel algorithms, which are derived from the classical alternating Schwarz method, are illustrated through several numerical examples using the reservoir simulator Athena.
Date: April 18, 2005
Creator: Garrido, I; Fladmark, G E; Espedal, M S & Lee, B
System: The UNT Digital Library
Residual Stress Measurements in Side Bonded Resistance Welds (open access)

Residual Stress Measurements in Side Bonded Resistance Welds

Resistance upset welding is used to attach small diameter machined tubes to small gas vessels. Recently there has been interest in determining the level of residual stresses caused by this attachment method and its influence on environmental interactions. A test program was initiated to determine the residual stresses present due to welding using the nominal weld parameters and varying the interference between the foot and the counter bore. In this paper, the residual stress measurement technique is described, the welding conditions are provided, and the residual stress due to welding at the nominal conditions are presented.
Date: April 18, 2005
Creator: Korinko, Paul
System: The UNT Digital Library
QGP and Modified Jet Fragmentation (open access)

QGP and Modified Jet Fragmentation

Recent progresses in the study of jet modification in hotmedium and their consequences in high-energy heavy-ion collisions are reviewed. In particular, I will discuss energy loss for propagating heavy quarks and the resulting modified fragmentation function. Medium modification of the parton fragmentation function due to quark recombination are formulated within finite temperature field theory and their implication on the search for deconfined quark-gluon plasma is also discussed.
Date: April 18, 2005
Creator: Wang, Xin-Nian
System: The UNT Digital Library
Exploring the Fast Ignition Approach to Fusion Energy (open access)

Exploring the Fast Ignition Approach to Fusion Energy

Probably the most famous equation in physics is Einstein's E=mc{sup 2}, which was contained within his fifth and final paper that was published in 1905. It is this relationship between energy ( E) and mass ( m) that the fusion process exploits to generate energy. When two isotopes of hydrogen (normally Deuterium and Tritium (DT)) fuse they form helium and a neutron. In this process some of the mass of the hydrogen is converted into energy. In the fast ignition approach to fusion a large driver (such as the NIF laser) is used to compress the DT fuel to extremely high densities and then is ''sparked'' by a high intensity, short-pulse laser. The short-pulse laser energy is converted to an electron beam, which then deposits its energy in the DT fuel. The energy of the electrons in this beam is so large that the electron's mass is increased according to Einstein theory of relativity. Understanding the transport of this relativistic electron beam is critical to the success of fast ignition and is the subject of this poster.
Date: April 18, 2005
Creator: Town, R. J.; Chung, H.; Cottrill, L. A.; Foord, M.; Hatchett, S. P.; Key, M. H. et al.
System: The UNT Digital Library