Methods for documenting the personally constructed reality of risk

To document an individual's longitudinal construction of risk is a logistically intensive task. To identify a logistically feasible approach, we review existing agent-based experience documentation approaches within the context of a specified risk source - performance of a transportation network. The most promising documentation method, GPS tracking, was then tested in a four month pilot study This study found that while GPS tracking documents an individual's activities in extreme detail, the psychological context of these activities is missing. To contextualize this data, the feasibility of applying three different hedonic psychology research methodologies is assessed. From the perspective offered by this pilot study, it is believed a daily survey documenting the individual's observed key experiences combined with a focused survey qualifying recent GPS documented experience variances shows potential for being a comprehensive and logistically feasible methodology for documenting an individual's longitudinal construction of risk

Kinetic modelling and molecular dynamics simulation of ultracold neutral plasmas including ionic correlations

A kinetic approach for the evolution of ultracold neutral plasmas including interionic correlations and the treatment of ionization/excitation and recombination/deexcitation by rate equations is described in detail. To assess the reliability of the approximations inherent in the kinetic model, we have developed a hybrid molecular dynamics method. Comparison of the results reveals that the kinetic model describes the atomic and ionic observables of the ultracold plasma surprisingly well, confirming our earlier findings concerning the role of ion-ion correlations [Phys. Rev. A {\bf 68}, 010703]. In addition, the molecular dynamics approach allows one to study the relaxation of the ionic plasma component towards thermodynamical equilibrium

New combined PIC-MCC approach for fast simulation of a radio frequency discharge at low gas pressure

A new combined PIC-MCC approach is developed for accurate and fast simulation of a radio frequency discharge at low gas pressure and high density of plasma. Test calculations of transition between different modes of electron heating in a ccrf discharge in helium and argon show a good agreement with experimental data. We demonstrate high efficiency of the combined PIC-MCC algorithm, especially for the collisionless regime of electron heating.Comment: 6 paged, 8 figure

Modeling of chemical processes in the low pressure capacitive RF discharges in a mixture of Ar/C2H2

We study the properties of a capacitive 13.56 MHz discharge properties with a mixture of Ar/C2H2 taking into account the plasmochemistry and growth of heavy hydrocarbons. A hybrid model was developed to combine the kinetic description for electron motion and the fluid approach for negative and positive ions transport and plasmochemical processes. A significant change of plasma parameters related to injection of 5.8% portion of acetylene in argon was observed and analyzed. We found that the electronegativity of the mixture is about 30%. The densities of negatively and positively charged heavy hydrocarbons are sufficiently large to be precursors for the formation of nanoparticles in the discharge volume.Comment: 11 pages, 14 figure

Critical collapse of collisionless matter - a numerical investigation

In recent years the threshold of black hole formation in spherically symmetric gravitational collapse has been studied for a variety of matter models. In this paper the corresponding issue is investigated for a matter model significantly different from those considered so far in this context. We study the transition from dispersion to black hole formation in the collapse of collisionless matter when the initial data is scaled. This is done by means of a numerical code similar to those commonly used in plasma physics. The result is that for the initial data for which the solutions were computed, most of the matter falls into the black hole whenever a black hole is formed. This results in a discontinuity in the mass of the black hole at the onset of black hole formation.Comment: 22 pages, LaTeX, 7 figures (ps-files, automatically included using psfig

Statistical kinetic treatment of relativistic binary collisions

In particle-based algorithms, the effect of binary collisions is commonly described in a statistical way, using Monte Carlo techniques. It is shown that, in the relativistic regime, stringent constraints should be considered on the sampling of particle pairs for collision, which are critical to ensure physically meaningful results, and that nonrelativistic sampling criteria (e.g., uniform random pairing) yield qualitatively wrong results, including equilibrium distributions that differ from the theoretical J\"uttner distribution. A general procedure for relativistically consistent algorithms is provided, and verified with three-dimensional Monte Carlo simulations, thus opening the way to the numerical exploration of the statistical properties of collisional relativistic systems.Comment: Accepted for publication as a Rapid Communication in Phys. Rev.

Numerical Modeling of Radiation-Dominated and QED-Strong Regimes of Laser-Plasma Interaction

Ultra-strong laser pulses can be so intense that an electron in the focused beam loses significant energy due to gamma-photon emission while its motion deviates via the radiation back-reaction. Numerical methods and tools designed to simulate radiation-dominated and QED-strong laser-plasma interactions are summarized here.Comment: 12 pages, 6 figure

Generation of ultra-short light pulses by a rapidly ionizing thin foil

A thin and dense plasma layer is created when a sufficiently strong laser pulse impinges on a solid target. The nonlinearity introduced by the time-dependent electron density leads to the generation of harmonics. The pulse duration of the harmonic radiation is related to the risetime of the electron density and thus can be affected by the shape of the incident pulse and its peak field strength. Results are presented from numerical particle-in-cell-simulations of an intense laser pulse interacting with a thin foil target. An analytical model which shows how the harmonics are created is introduced. The proposed scheme might be a promising way towards the generation of attosecond pulses. PACS number(s): 52.40.Nk, 52.50.Jm, 52.65.RrComment: Second Revised Version, 13 pages (REVTeX), 3 figures in ps-format, submitted for publication to Physical Review E, WWW: http://www.physik.tu-darmstadt.de/tqe

Reaching Inward Not Outward: Marketing via the Internet at the UK 2010 General Election

The Internet has been to date used as a space for simple promotion by political parties; websites present an opportunity for the delivery of non-mediated communication directly to the online audience and nothing more. However, new patterns in usage during campaigns, particularly that of Barack Obama, aided by the technological innovations that fall under the umbrella of Web 2.0, offer new models of online political communication. Through an analysis of the websites and linked online presences of six parties that stood across the UK at the 2010 General Election, we find a dual strategy for Internet campaigning emerging. The persuasive traditions of electioneering remain a feature; however, the key emergent function is one of internal marketing to party supporters and activists. Large sections of party websites are being dedicated to harnessing supporters and converting them to being donators, promoters, and campaigners both online and offline. This suggests that the Internet is increasingly embedded within election communication and online communication strategies are becoming a feature of most of the parties' marketing communication mix. © 2013 Copyright Taylor and Francis Group, LLC