Download or read book Hybrid Particle in cell PIC Simulation of Heat Transfer and Ionization Balance in Overdense Plasmas Irradiated by Subpicosecond Pulse Lasers written by Alekseĭ Gennadʹevich Zhidkov and published by . This book was released on 1998 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hybrid Particle in cell pic Simulation of Heat Trnasfer Ionization Balance in Overdense Plasmas Irradiated by Subpicosecond Pulse Lasers written by A. Zhidkov and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Technical Publications by JAERI Staff in written by Nihon Genshiryoku Kenkyujo and published by . This book was released on 1998 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Methods in Plasma Simulation written by and published by . This book was released on 1990 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of implicit methods of particle-in-cell (PIC) computer simulation in recent years, and their merger with older hybrid methods have created a new arsenal of simulation techniques for the treatment of complex practical problems in plasma physics. The new implicit hybrid codes are aimed at transitional problems that lie somewhere between the long time scale, high density regime associated with MHD modeling, and the short time scale, low density regime appropriate to PIC particle-in-cell techniques. This transitional regime arises in ICF coronal plasmas, in pulsed power plasma switches, in Z-pinches, and in foil implosions. Here, we outline how such a merger of implicit and hybrid methods has been carried out, specifically in the ANTHEM computer code, and demonstrate the utility of implicit hybrid simulation in applications. 25 refs., 5 figs.

Download or read book Particle in cell Simulations of Bounded Plasma Discharges Applied to Low Pressure High Density Sources and Positive Columns written by Emi Kawamura and published by . This book was released on 2003 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hybrid Particle in cell Simulations of Relativistic Plasmas written by Tobias Tückmantel and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plasma Neutralization Models for Intense Ion Beam Transport in Plasma written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma neutralization of an intense ion pulse is of interest for many applications, including plasma lenses, heavy ion fusion, cosmic ray propagation, etc. An analytical electron fluid model has been developed based on the assumption of long charge bunches (l[sub b]” r[sub b]). Theoretical predictions are compared with the results of calculations utilizing a particle-in-cell (PIC) code. The cold electron fluid results agree well with the PIC simulations for ion beam propagation through a background plasma. The analytical predictions for the degree of ion beam charge and current neutralization also agree well with the results of the numerical simulations. The model predicts very good charge neutralization (>99%) during quasi-steady-state propagation, provided the beam pulse duration[tau][sub b] is much longer than the electron plasma period 2[pi]/[omega][sub p], where[omega][sub p]= (4[pi]e[sup 2]n[sub p]/m)[sup 1/2] is the electron plasma frequency, and n[sub p] is the background plasma density. In the opposite limit, the beam pulse excites large-amplitude plasma waves. The analytical formulas derived in this paper can provide an important benchmark for numerical codes, and provide scaling relations for different beam and plasma parameters.

Download or read book Particle Simulation of Plasma Breakdown Produced by Multiple Picosecond Laser Pulses written by Quan Zhang and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Two dimensional Particle in cell PIC Model of an Axisymmetric Electron cyclotron resonance ECR Plasma processing System written by Kaihan Abidi Ashtiani and published by . This book was released on 1995 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi dimensional Hybrid simulation Techniques in Plasma Physics written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-dimensional hybrid simulation models have been developed for use in studying plasma phenomena on extended time and distance scales. The models make fundamental use of the small Debye length or quasi-neutrality assumption. The ions are modeled by particle-in-cell (PIC) techniques while the electrons are considered a collision-dominated fluid. The fields are calculated in the nonradiative Darwin limit. Some electron inertial effects are retained in the Finite Electron Mass model (FEM). In this model, the quasi-neutral counterpart of Poisson's equation is obtained by first summing the electron and ion momentum equations and then taking the quasi-neutral limit. In the Zero Electron Mass (ZEM) model explicit use is made of the axisymmetric properties of the model to decouple the components of the model equations. Equations to self-consistently advance the electron temperature have recently been added to the scheme. The model equations which result from these considerations are two coupled, nonlinear, second order partial differential equations.

Download or read book Acta Helvetica physico medica written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book THE IMPLICIT HYBRID written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent inventions in pulse power switching, fast laser-driven thermonuclear ignition, and short pulse radiography have demanded a dramatic increase in the capabilities of plasma simulation tools. Multifluid, multi-component, fluid and kinetic models are needed for plasmas spanning thousands of Debye lengths and thousands of plasma periods. Such plasmas manifest both dense and tenuous regions, including or excluding magnetic fields and collisional resistivity. The problems of interest can dwell in a transition regime with limits traditionally treated by resistive MHD and and/or collisional particle-in-cell (PIC) methods. The ANTHEM implicit hybrid simulation model is under development to meet these challenges. This presentation will outline its past and current features, and review results typical of short-pulse laser applications.

Download or read book Electromagnetic particle in cell Plasma Simulation written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ''PIC'' simulation tracks particles through electromagnetic fields calculated self-consistently from the charge and current densities of the particles themselves, external sources, and boundaries. Already used extensively in plasma physics, such simulations have become useful in the design of accelerators and their r.f. sources. 5 refs.

Download or read book Collaborative Research written by and published by . This book was released on 2016 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interactions of flows of partially ionized, magnetized plasma are frequently accompanied by the presence of both thermal and non-thermal (pickup) ion components. Such interactions cannot be modeled using traditional MHD equations and require more advanced approaches to treat them. If a nonthermal component of ions is formed due to charge exchange and collisions between the thermal (core) ions and neutrals, it experiences the action of magnetic field, its distribution function is isotropized, and it soon acquires the velocity of the ambient plasma without being thermodynamically equilibrated. This situation, e. g., takes place in the outer heliosphere - the part of interstellar space beyond the solar system whose properties are determined by the solar wind interaction with the local interstellar medium. This is also possible in laboratory, at million degrees and above, when plasma is conducting electricity far too well, which makes Ohmic heating ineffective. To attain the target temperatures one needs additional heating eventually playing a dominant role. Among such sources is a so-called neutral particle beam heating. This is a wide-spread technique (Joint European Torus and International Thermonuclear Experimental Reactor experiments) based on the injection of powerful beams of neutral atoms into ohmically preheated plasma. In this project we have investigated the energy and density separation between the thermal and nonthermal components in the solar wind and interstellar plasmas. A new model has been developed in which we solve the ideal MHD equations for mixture of all ions and the kinetic Boltzmann equation to describe the transport of neutral atoms. As a separate capability, we can treat the flow of neutral atoms in a multi-component fashion, where neutral atoms born in each thermodynamically distinct regions are governed by the Euler gas dynamic equations. We also describe the behavior of pickup ions either kinetically, using the Fokker-Planck equation, or as a separate fluid. Our numerical simulations have demonstrated that pickup ions play a major role in the interaction of the solar wind and (partially ionized) interstellar medium plasmas. Our teams have investigated the stability of the surface (the heliopause) that separates the solar wind from the local interstellar medium, the transport of galactic cosmic rays, the properties of the heliotail flow, and modifications to the bow wave in front of the heliopause due to charge exchange between the neutral H atoms born in the solar wind and interstellar ions. Modeling results have been validated against observational data, such as obtained by the Interstellar Boundary Explorer (IBEX), and made it possible to shed light on the structure of energetic neutral atom maps created by this spacecraft.. We have also demonstrated that charge-exchange modulated heliosphere is a source of anisotropy of the multi-TeV cosmic ray flux observed in a number of Earth-bound air shower experiments. Newly developed codes are implemented within a Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS), a publicly available code being developed by our team for over 12 years. MS-FLUKSS scales well up to 160,000 computing cores and has been ported on major supercomputers in the country. Efficient parallelization and data choreography in the continuum simulation modules are provided by Chombo, an adaptive mesh refinement framework managed by Phillip Colella's team at LBNL. We have implemented in-house, hybrid (MPI+OpenMP) parallelization of the kinetic modules that solve the Boltzmann equation with a Monte Carlo method. Currently, the kinetic modules are being rewritten to take advantage of the modern CPU-GPU supercomputer architecture. The scope of the project allowed us to enhance plasma research and education in such broad, multidis- ciplinary field as physics of partially ionized plasma and its application to space physics and fusion science. Besides the impact on the modeling of complex ...

Download or read book Frontiers in High Energy Density Physics written by National Research Council and published by National Academies Press. This book was released on 2003-05-11 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent scientific and technical advances have made it possible to create matter in the laboratory under conditions relevant to astrophysical systems such as supernovae and black holes. These advances will also benefit inertial confinement fusion research and the nation's nuclear weapon's program. The report describes the major research facilities on which such high energy density conditions can be achieved and lists a number of key scientific questions about high energy density physics that can be addressed by this research. Several recommendations are presented that would facilitate the development of a comprehensive strategy for realizing these research opportunities.

Download or read book A Full Electromagnetic Particle in Cell Code To Model Collision less Plasmas in Magnetic Traps written by E. A. Orozco and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A lot of plasma physics problems are not amenable to exact solutions due to many reasons. It is worth mentioning among them, for example, nonlinearity of the motion equations, variable coefficients or non lineal conditions on known or unknown borders. To solve these problems, different types of approximations which are combinations of analytical and numerical simulation methods are put into practice. The problem of plasma behavior in numerous varieties of a minimum-B magnetic trap where the plasma is heated under electron cyclotron resonance (ECR) conditions is the subject of numerical simulation studies. At present, the ECR minimum-B trap forms the principal part of the multi-charge ion sources.There are different numerical methods to model plasmas. Depending of both temperature and concentration, these can be classified in three main groups: fluid models, kinetic models and hybrid models. The fluid models are the most simple way to describe the plasma from macroscopic quantities, which are used for the study of highly collisional plasmas where the mean free path is much smaller than size of plasma (l_mfp “ L). The kinetic models are the most fundamental way to describe plasmas through the distribution function in phase-space for each particle specie; which are used for the study of weakly collisional (l_mfp ∼ L) or collision-less plasmas (l_mfp ” L) from the solution of the Boltzmann or Vlasov equation, respectively [2]. For kinetic simulations there are different method to solve the Boltzmann or Vlasov equation, being the Particle-In-Cell (PIC) codes one the most popular. The hybrid model combine both the fluid and kinetic models, treating some components of the system as a fluid, and others kinetically; which are used for the study of plasmas, may use the PIC method for the kinetic treatment of some species, while other species (that are Maxwellian) are simulated with a fluid model.In this work, a scheme of the relativistic Particle-in-Cell (PIC) code elaborated for an ECR plasma heating study in minimum-B traps is presented. For a PIC numerical simulation, the code is applied to an ECR plasma confined in a minimum-B trap formed by two current coils generating a mirror magnetic configuration and a hexapole permanent magnetic bars to suppress the MHD instabilities.The plasma is maintained in a cylindrical chamber excited at TE_111 mode by 2.45 GHz microwave power. In the obtained magnetostatic field, the ECR conditions are fulfilled on a closed surface of ellipsoidal type. Initially, a Maxwellian homogeneous plasma from ionic temperature of 2 eV being during 81.62 ns, that correspond to 200 cycles of microwaves with an amplitude in the electric field of 1 kV/cm is heated. The electron population can be divided conditionally into a cold group of energies smaller than 0.2 keV, a warm group whose energies are in a range of 3 - 10 keV and hot electrons whose energies are found higher than 10 keV.

Download or read book Laser plasma Interactions and Hot Electron Generation in Inertial Confinement Fusion written by Jun Li and published by . This book was released on 2016 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis studies several problems related to hot (energetic) electron generation in laser-plasma interactions in inertial confinement fusion (ICF). We study laserplasma instabilities (LPI) that can generate hot electrons in direct drive ICF under a range of laser intensities relevant to both the conventional hot-spot ignition and shock ignition. We study the in uence of LPI and hot electrons on the hydrodynamic evolution of ICF targets. We study hot electron generation in intense laser-plasma interactions in fast ignition cone targets. We also study how to implement particle collisions, which are important to hot electron generation in LPI, in Particle-in-Cell (PIC) codes on Graphic Process Units (GPU's). We find that ion density modulations can turn convective two-plasmon decay (TPD) and stimulated Raman scattering (SRS) instabilities to absolute ones in the region below the quarter critical density (nc=4). In this region, our uid simulations show that when a sinusoidal density modulation is superimposed on a linear density profile, convective two-plasmon decay (TPD) and stimulated Raman scattering (SRS) instabilities can become absolutely unstable under realistic direct-drive ICF conditions. Analysis of a three-wave model with a two-slope density profile shows that a sufficiently large change of the density gradient in a linear density profile can turn convective instabilities into absolute ones. An analytical expression is given for the threshold of the gradient change, which depends on the convective gain only. Growth rates for the absolute modes are also obtained. The threshold and growth rates from the two-slope profile are found to approximate those under sinusoidal modulations. These results explain the origin of the TPD modes below the nc=4 surface that in previous research were found to be critical to hot electron generation. Combining PIC and hydrodynamics simulations, we study the LPI and hydro evolution of coronal plasmas in an OMEGA EP[J.H. Kelly et al., 2006] long-scalelength experiment[Hu et al., 2013; Haberberger et al., 2014] with planar targets. Plasma and laser conditions are first obtained in a DRACO hydro simulation with only inverse-bremsstrahlung absorption. Using these conditions, an OSIRIS PIC simulation is performed to study laser absorption and hot-electron generation caused by LPI near the nc=4 region. The obtained information from the PIC simulation is subsequently coupled back to another DRACO simulation to examine how the LPI affect the overall hydrodynamics. The results show that the LPIinduced laser absorption can increase the electron temperature due to local heating by plasma waves. But it does not significantly change the density scale length in the corona because the high heat conductivity can spread the higher energy deposited near the nc=4 region in a wider region, and the portion of the energy carried by the hot electrons going towards high density region is still deposited beyond the nc=4 region. The collisional effects can affect the hot electron generation by damping the coupling waves of TPD and SRS instabilities. We have benchmarked the collision package in OSIRIS and adapted this package to a PIC code on graphics processors (GPU) with CUDA. The collision package is based on the cumulative collision theory, which treats a succession of small-angle binary collisions as a unique binary collision with a large scattering angle. It uses the computing cell in the GPUPIC code as the collision cell, and randomly pairs the particles in each collision cell for collision. In this process, it takes advantage of the fast on-chip shared memory and gets a remarkable performance. The benchmarks show that this collision package only needs to be called every 100 steps, and has a performance of 0:07 - 0:09ns=particle - step, only a 1:4% increase over the 5:36ns=particle - step without collisions on a Nvidia GTX 680 GPU. Test problems of beam-plasma scattering and electron plasma wave damping show that the collision frequencies calculated from the simulation results are consistent with theory. Hot electron generation is also important in fast ignition where typical laser intensities are higher than the hot-spot ignition or shock ignition. We perform PIC simulations for a cone-in-shell integrated fast-ignition experiment at the Omega Laser Facility[Boehly et al., 1997] with the initial plasma density profile taken from hydrodynamic simulations of the prepulse interaction with the gold cone. Hotelectron generation from laser-pre-plasma interactions and transport up to 100nc are studied. The simulations show a mean divergence half-angle of 68 degrees and 50% absorption for the hot electrons. The results show that the hot electrons are dominated in number by low-energy electrons but in energy by multi-MeV electrons. Electron transport between 5 and 100 nc is ballistic. In the late stage of the simulation, hot electron generation is largely independent of polarization, indicating a stochastic hot-electron-generation mechanism.