Radiation Damping and Quantum Excitation for Longitudinal Charged Particle Dynamics in the Thermal Wave Model

On the basis of the recently proposed {\it Thermal Wave Model (TWM) for particle beams}, we give a description of the longitudinal charge particle dynamics in circular accelerating machines by taking into account both radiation damping and quantum excitation (stochastic effect), in presence of a RF potential well. The longitudinal dynamics is governed by a 1-D Schr\"{o}dinger-like equation for a complex wave function whose squared modulus gives the longitudinal bunch density profile. In this framework, the appropriate {\it r.m.s. emittance} scaling law, due to the damping effect, is naturally recovered, and the asymptotic equilibrium condition for the bunch length, due to the competition between quantum excitation (QE) and radiation damping (RD), is found. This result opens the possibility to apply the TWM, already tested for protons, to electrons, for which QE and RD are very important.Comment: 10 pages, plain LaTeX; published in Phys. Lett. A194 (1994) 113-11

Classical and Quantum-like approaches to Charged-Particle Fluids in a Quadrupole

A classical description of the dynamics of a dissipative charged-particle fluid in a quadrupole-like device is developed. It is shown that the set of the classical fluid equations contains the same information as a complex function satisfying a Schrodinger-like equation in which Planck's constant is replaced by the time-varying emittance, which is related to the time-varying temperature of the fluid. The squared modulus and the gradient of the phase of this complex function are proportional to the fluid density and to the current velocity, respectively. Within this framework, the dynamics of an electron bunch in a storage ring in the presence of radiation damping and quantum-excitation is recovered. Furthermore, both standard and generalized (including dissipation) coherent states that may be associated with the classical particle fluids are fully described in terms of the above formalism.Comment: LaTex, to appear in Physica Script

Envelope solitons induced by high-order effects of light-plasma interaction

The nonlinear coupling between the light beams and non-resonant ion density perturbations in a plasma is considered, taking into account the relativistic particle mass increase and the light beam ponderomotive force. A pair of equations comprising a nonlinear Schrodinger equation for the light beams and a driven (by the light beam pressure) ion-acoustic wave response is derived. It is shown that the stationary solutions of the nonlinear equations can be represented in the form of a bright and dark/gray soliton for one-dimensional problem. We have also present a numerical analysis which shows that our bright soliton solutions are stable exclusively for the values of the parameters compatible with of our theory.Comment: 9 pages, 5 figure

Nonlocal effects in high energy charged particle beams

Within the framework of the thermal wave model, an investigation is made of the longitudinal dynamics of high energy charged particle beams. The model includes the self-consistent interaction between the beam and its surroundings in terms of a nonlinear coupling impedance, and when resistive as well as reactive parts are included, the evolution equation becomes a generalised nonlinear Schroedinger equation including a nonlocal nonlinear term. The consequences of the resistive part on the propagation of particle bunches are examined using analytical as well as numerical methods.Comment: 6 pages, 6 figures, uses RevTeX

An interprofessional, intercultural, immersive short-term study abroad program: public health and service systems in rome

The purpose of this paper is to describe a short-term study abroad program that exposes engineering and nursing undergraduate students from the United States and Italy to an intercultural and interprofessional immersion experience. Faculty from Purdue University and Sapienza Università di Roma collaborated to design a technical program that demonstrates the complementary nature of engineering and public health in the service sector, with Rome as an integral component of the program. Specifically, the intersection of topics including systems, reliability, process flow, maintenance management, and public health are covered through online lectures, in-class activities and case study discussions, field experiences, and assessments. Herein, administrative issues such as student recruitment, selection, and preparation are elucidated. Additionally, the pedagogical approach used to ensure constructive alignment among the program goals, the intended learning outcomes, and the teaching and learning activities is described. Finally, examples of learning outcomes resulting from this alignment are provided

Experimental and numerical investigation on forced convection in circular tubes with nanofluids

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.In this paper an experimental and numerical study to investigate the convective heat transfer characteristics of fully developed turbulent flow of a water–Al2O3 nanofluid in a circular tube is presented. The numerical simulations are accomplished on the experimental test section configuration. In the analysis, the fluid flow and the thermal field are assumed axial-symmetric, two-dimensional and steady state. The single-phase model is employed to model the nanofluid mixture and k-ε model is used to describe the turbulent fluid flow. Experimental and numerical results are carried out for different volumetric flow rates and nanoparticles concentration values. Heat transfer convective coefficients as a function of flow rates and Reynolds numbers are presented. The results indicate that the heat transfer coefficients increase for all nanofluids concentrations compared to pure water at increasing volumetric flow rate. Heat transfer coefficient increases are observed at assigned volumetric flow rate for nanofluid mixture with higher concentrations whereas Nusselt numbers present lower values than the ones for pure water

Landau Damping and Coherent Structures in Narrow-Banded 1+1 Deep Water Gravity Waves

We study the nonlinear energy transfer around the peak of the spectrum of surface gravity waves by taking into account nonhomogeneous effects. In the narrow-banded approximation the kinetic equation resulting from a nonhomogeneous wave field is a Vlasov-Poisson type equation which includes at the same time the random version of the Benjamin-Feir instability and the Landau damping phenomenon. We analytically derive the values of the Phillips' constant $\alpha$ and the enhancement factor $\gamma$ for which the narrow-banded approximation of the JONSWAP spectrum is unstable. By performing numerical simulations of the nonlinear Schr\"{o}dinger equation we check the validity of the prediction of the related kinetic equation. We find that the effect of Landau damping is to suppress the formation of coherent structures. The problem of predicting freak waves is briefly discussed.Comment: 4 pages, 3 figure

High-quality GeV-scale electron bunches with the Resonant Multi-Pulse Ionization Injection

Recently a new injection scheme for Laser Wake Field Acceleration, employing a single 100-TW-class laser system, has been proposed. In the Resonant Multi-Pulse Ionization injection (ReMPI) a resonant train of pulses drives a large amplitude plasma wave that traps electrons extracted from the plasma by further ionization of a high-Z dopant (Argon in the present paper). While the pulses of the driver train have intensity below the threshold for the dopant's ionization, the properly delayed and frequency doubled (or more) ionization pulse possesses an electric field large enough to extract electrons, though its normalized amplitude is well below unity. In this paper we will report on numerical simulations results aimed at the generation of GeV-scale bunches with normalized emittance and {\it rms} energy below $80\, nm \times rad$ and $0.5\, \%$, respectively. Analytical consideration of the FEL performance for a $1.3\, GeV$ bunch will be also reported.Comment: EAAC 2017 Conference, Elba, Ital