146 research outputs found
On the stochastic dissemination of faults in an admissible network
The dynamic distribution of faults in a general type network is discussed. The starting point is a uniquely branched network in which each pair of nodes is connected by a single branch. Mathematical expressions for the uniquely branched network transition matrix are derived to show that sufficient stationarity exists to ensure the validity of the use of the Markov Chain model to analyze networks. In addition the conditions for the use of Semi-Markov models are discussed. General mathematical expressions are derived in an examination of branch redundancy techniques commonly used to increase reliability
Mathematical physics approaches to lightning discharge problems
Mathematical physics arguments useful for lightning discharge and generation problems are pursued. A soliton Ansatz for the lightning stroke is treated including a charge generation term which is the ultimate source for the phenomena. Equations are established for a partially ionized plasma inding the effects of pressure, magnetic field, electric field, gravitation, viscosity, and temperature. From these equations is then derived the non-stationary generalized Ohm's Law essential for describing field/current density relationships in the horizon channel of the lightning stroke. The discharge initiation problem is discussed. It is argued that the ionization rate drives both the convective current and electric displacement current to increase exponentially. The statistical distributions of charge in the thundercloud preceding a lightning dischage are considered. The stability of the pre-lightning charge distributions and the use of Boltzmann relaxational equations to determine them are discussed along with a covered impedance path provided by the aircraft
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Multiphoton physics with x-rays: Two photon K-shell ionization of chlorine
A calculation of the two X-ray K-shell photoionization cross section of chlorine will be presented and the feasibility of an experiment will be discussed
Correlation Exponent and Anomalously Localized States at the Critical Point of the Anderson Transition
We study the box-measure correlation function of quantum states at the
Anderson transition point with taking care of anomalously localized states
(ALS). By eliminating ALS from the ensemble of critical wavefunctions, we
confirm, for the first time, the scaling relation z(q)=d+2tau(q)-tau(2q) for a
wide range of q, where q is the order of box-measure moments and z(q) and
tau(q) are the correlation and the mass exponents, respectively. The influence
of ALS to the calculation of z(q) is also discussed.Comment: 6 pages, 3 figure
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Multiphoton physics with x-rays: Two photon K-shell ionization of chlorine
A calculation of the two X-ray K-shell photoionization cross section of chlorine will be presented and the feasibility of an experiment will be discussed
Critical level statistics and anomalously localized states at the Anderson transition
We study the level-spacing distribution function at the Anderson
transition by paying attention to anomalously localized states (ALS) which
contribute to statistical properties at the critical point. It is found that
the distribution for level pairs of ALS coincides with that for pairs of
typical multifractal states. This implies that ALS do not affect the shape of
the critical level-spacing distribution function. We also show that the
insensitivity of to ALS is a consequence of multifractality in tail
structures of ALS.Comment: 8 pages, 5 figure
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Simulations of the radiation-flow within a silica-aerogel target
We propose to field a series of experiments to study the flow of radiation through silica-aerogel targets. The soft x-rays are generated by the Z-machine at Sandia National Laboratories. We have completed simulations of the experiments using 2-D Lagrangian and Eulerian codes. The results of the calculations for one of the targets are presented here
Ejection Energy of Photoelectrons in Strong Field Ionization
We show that zero ejection energy of the photoelectrons is classically
impossible for hydrogen-like ions, even when field ionization occurs
adiabatically. To prove this we transform the basic equations to those
describing two 2D anharmonic oscillators. The same method yields an alternative
way to derive the anomalous critical field of hydrogen-like ions. The
analytical results are confirmed and illustrated by numerical simulations. PACS
Number: 32.80.RmComment: 7 pages, REVTeX, postscript file including the figures is available
at http://www.physik.th-darmstadt.de/tqe/dieter/publist.html or via anonymous
ftp from ftp://tqe.iap.physik.th-darmstadt.de/pub/dieter/publ_I_pra_pre.ps,
accepted for publication in Phys. Rev.
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Measurement and simulation of jet mass caused by a high-aspect ratio pertubation
Inertial confinement fusion (ICF) capsule performance can be negatively impacted by the presence of hydrodynamic instabilities. To perform a gas fill on an ICF capsule current plans involve drilling a small hole and inserting a fill tube to inject the gas mixture into the capsule. This introduces a perturbation on the capsule, which can seed hydrodynamic instabilities. The small hole can cause jetting of the shell material into the gas, which might adversely affect the capsule performance. We have performed simulations and experiments to study the hydrodynamic evolution of jets from high-aspect ratio holes, such as the fill tube hole. Although simulations using cold materials over predict the amount of mass in the jet, when a reasonable amount of preheat (< 1 eV) is introduced, the simulations are in better agreement with the experiment
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