Download or read book A Kinetic Theory Based Numerical Study of Core Collapse Supernova Dynamics written by Terrance T. Strother and published by . This book was released on 2009 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Study of Rotating Core Collapse Supernovae written by Mark Tobias Bollenbach and published by . This book was released on 2002 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Open Issues In Core Collapse Supernova Theory written by Anthony Mezzacappa and published by World Scientific. This book was released on 2005-12-01 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efforts to uncover the explosion mechanism of core collapse supernovae and to understand all of their associated phenomena have been ongoing for nearly four decades. Despite this, our theoretical understanding of these cosmic events remains limited; two- and three-dimensional modeling of these events is in its infancy. Most of the modeling efforts over the past four decades have, by necessity, been constrained to spherical symmetry, with the first two-dimensional, albeit simplified, models appearing only during the last decade. Simulations to understand the complex interplay between the turbulent stellar core fluid flow, its magnetic fields, the neutrinos produced in and emanating from the proto-neutron star, the stellar core rotation, and the strong gravitational fields have yet to be performed. Only subsets of these fundamental ingredients have been included in the models thus far, often with approximation.The purpose of this volume is to identify the outstanding issues that remain in order to come to a complete understanding of these important astrophysical events. As the book focuses on open issues rather than the current state of the art in the field — although the latter will certainly be discussed — it will remain relevant for some time.

Download or read book Numerical Experiments in Core collapse Supernova Hydrodynamics written by Rodrigo Andres Fernandez and published by . This book was released on 2009 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The explosion of massive stars involves the formation of a shock wave. In stars that develop iron cores, this shock wave stalls on its way out due to neutrino emission and the breakup of heavy nuclei flowing through the shock. For the explosion to succeed, a fraction of the gravitational binding energy of the collapsed core that is radiated in neutrinos needs to be absorbed by the material below the shock. How much energy is needed depends on the interplay between non-spherical hydrodynamic instabilities, neutrino heating, and nuclear dissociation. This thesis seeks to understand this interplay through numerical experiments that model the key physical components of the system and separate them out to examine their individual effects. Specifically, one- and two-dimensional time-dependent hydrodynamic simulations are performed to study the effects of non-spherical shock oscillations, neutrino-driven convection, and alpha particle recombination on the dynamics of the system and the critical heating rate for explosion.We find that nuclear dissociation has a significant effect on the linear stability and saturation amplitude of shock oscillations. At the critical neutrino heating rate for an explosion, convection due to a negative entropy gradient plays a major role in driving dipolar shock motions. One dimensional explosions are due to a global instability involving the advection of entropy perturbations from the shock to the region where the accretion flow cools due to neutrino emission. Large scale shock expansions in two-dimensions are due to a finite amplitude instability involving the balance between buoyancy forces and the ram pressure of the flow upstream of the shock. During these expansions, a significant amount of energy is released when nucleons recombine into alpha particles, constituting a significant last step in the transition to explosion. The critical neutrino heating rate for an explosion depends sensitively on the starting radius of the shock relative to the radius at which the binding energy of an alpha particle is comparable to the gravitational binding energy.

Download or read book Numerical Experiments in Core collapse Supernova Hydrodynamics written by Rodrigo Andres Fernandez and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The explosion of massive stars involves the formation of a shock wave. In stars that develop iron cores, this shock wave stalls on its way out due to neutrino emission and the breakup of heavy nuclei flowing through the shock. For the explosion to succeed, a fraction of the gravitational binding energy of the collapsed core that is radiated in neutrinos needs to be absorbed by the material below the shock. How much energy is needed depends on the interplay between non-spherical hydrodynamic instabilities, neutrino heating, and nuclear dissociation. This thesis seeks to understand this interplay through numerical experiments that model the key physical components of the system and separate them out to examine their individual effects. Specifically, one- and two-dimensional time-dependent hydrodynamic simulations are performed to study the effects of non-spherical shock oscillations, neutrino-driven convection, and alpha particle recombination on the dynamics of the system and the critical heating rate for explosion. We find that nuclear dissociation has a significant effect on the linear stability and saturation amplitude of shock oscillations. At the critical neutrino heating rate for an explosion, convection due to a negative entropy gradient plays a major role in driving dipolar shock motions. One dimensional explosions are due to a global instability involving the advection of entropy perturbations from the shock to the region where the accretion flow cools due to neutrino emission. Large scale shock expansions in two-dimensions are due to a finite amplitude instability involving the balance between buoyancy forces and the ram pressure of the flow upstream of the shock. During these expansions, a significant amount of energy is released when nucleons recombine into alpha particles, constituting a significant last step in the transition to explosion. The critical neutrino heating rate for an explosion depends sensitively on the starting radius of the shock relative to the radius at which the binding energy of an alpha particle is comparable to the gravitational binding energy.

Download or read book The Explosion Mechanism of Core Collapse Supernovae written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The explosion of core-collapse supernova depends on a sequence of events taking place in less than a second in a region of a few hundred kilometers at the center of a supergiant star, after the stellar core approaches the Chandrasekhar mass and collapses into a proto-neutron star, and before a shock wave is launched across the stellar envelope. Theoretical efforts to understand stellar death focus on the mechanism which transforms the collapse into an explosion. Progress in understanding this mechanism is reviewed with particular attention to its asymmetric character. We highlight a series of successful studies connecting observations of supernova remnants and pulsars properties to the theory of core-collapse using numerical simulations. The encouraging results from first principles models in axisymmetric simulations is tempered by new puzzles in 3D. The diversity of explosion paths and the dependence on the pre-collapse stellar structure is stressed, as well as the need to gain a better understanding of hydrodynamical and MHD instabilities such as SASI and neutrino-driven convection. The shallow water analogy of shock dynamics is presented as a comparative system where buoyancy effects are absent. This dynamical system can be studied numerically and also experimentally with a water fountain. Lastly, we analyse the potential of this complementary research tool for supernova theory. We also review its potential for public outreach in science museums.

Download or read book The Physics Of Supernovae And Their Mathematical Models written by Alexey G Aksenov and published by World Scientific. This book was released on 2024-03-06 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is dedicated to the theory of supernovae, focusing on new computational methods and simulations. It contains three parts: basic principles, numerical methods, and applications. The first part contains a non-formal introduction into the basics of supernovae, Boltzmann kinetic equations — with details of two particles reaction rate calculations — and the transformation of Boltzmann kinetic equations into hydrodynamic elements of statistical physics. It also contains the equation of state for matter of high energy density, with details of calculations for thermodynamic parameters, weak interactions, reaction rate details, and thermonuclear burning. The second part introduces elements of computational physics.The book closes with a presentation of original thought regarding the regime of burning in degenerate carbon-oxygen cores, a neutrino transport in Type II supernovae, a simulation of general relativity (GR) coalescence of neutron stars, aspherical nucleosynthesis in a core-collapse supernova, and thermalization in a pair of plasma winds from a compact strange star.This book brings together generally accepted simulations methods as well as original material written by two respected members of Russian research groups: the Keldysh Institute of Applied Mathematics and Institute of Theoretical and Experimental Physics. It contains the necessary information for a person to start independent research in this fast-developing field, and is therefore an important read for new researchers in this subject.

Download or read book Open Issues in Core Collapse Supernova Theory written by Anthony Mezzacappa and published by World Scientific. This book was released on 2005 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efforts to uncover the explosion mechanism of core collapse supernovae and to understand all of their associated phenomena have been ongoing for nearly four decades. Despite this, our theoretical understanding of these cosmic events remains limited; two- and three-dimensional modeling of these events is in its infancy. Most of the modeling efforts over the past four decades have, by necessity, been constrained to spherical symmetry, with the first two-dimensional, albeit simplified, models appearing only during the last decade. Simulations to understand the complex interplay between the turbulent stellar core fluid flow, its magnetic fields, the neutrinos produced in and emanating from the proto-neutron star, the stellar core rotation, and the strong gravitational fields have yet to be performed. Only subsets of these fundamental ingredients have been included in the models thus far, often with approximation. The purpose of this volume is to identify the outstanding issues that remain in order to come to a complete understanding of these important astrophysical events. As the book focuses on open issues rather than the current state of the art in the field OCo although the latter will certainly be discussed OCo it will remain relevant for some time."

Download or read book Sensitivity of Neutrino driven Core collapse Supernova Models to the Microphysical Equation of State written by Ryan Elliott Landfield and published by . This book was released on 2018 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this dissertation is to explore the sensitivity of neutrino-driven core collapse supernova physics to the microphysical equation of state of the stellar matter. Core collapse supernovae result from the gravitational collapse and ensuing explosion of massive stars. The most fundamental question in core collapse supernova (CCSN) theory is the mechanism of shock revival leading to the observed supernova explosion. The leading scenario is that neutrinos trapped in the proto-neutron star (PNS) during its formation escape and reheat the inner shock, reviving the shockwave, which expands outward, ejecting the star's outer shells into space. Given the central importance of the delayed heating mechanism to the dynamics of CCSNe, detailed studies of the dynamics of the neutrino heating mechanism, neutrino and gravitational wave (GW) signatures, and the dependence on both neutrino-matter interaction rates and the nuclear equation of state (EOS) are needed. The first direct detection of a GW emission from a CCSN would allow for a qualitative investigation into the accuracy of existing nuclear-force models via the EOS. Hence accurate CCSN numerical models are imminently necessary to predict and interpret such GW signatures. A tandem measurement of neutrino signature modulations and GWs would provide direct information about the CCSN mechanism and further our insight into the origins of neutron star rotation and kicks. In order to enhance the computational capability of the ORNL/UTK CCSN simulations, firstly I have developed the capacity to implement different pre-processed state-of-the-art EOS tables in the ORNL/UTK multi-D SN code CHIMERA. I have developed the multi-purpose EOS/Opacity table repository WeakLib for this purpose. Secondly, I have implemented these different EOS in 1D and 2D CHIMERA to study the impact of the EOS on the collapse, bounce, and post-bounce dynamics of the CCSNe explosion, as well as the impact on neutrino emission signals.

Download or read book Stellar Collapse written by Chris L. Fryer and published by Springer Science & Business Media. This book was released on 2004-04-30 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supernovae, hypernovae and gamma-ray bursts are among the most energetic explosions in the universe. The light from these outbursts is, for a brief time, comparable to billions of stars and can outshine the host galaxy within which the explosions reside. Most of the heavy elements in the universe are formed within these energetic explosions. Surprisingly enough, the collapse of massive stars is the primary source of not just one, but all three of these explosions. As all of these explosions arise from stellar collapse, to understand one requires an understanding of the others. Stellar Collapse marks the first book to combine discussions of all three phenomena, focusing on the similarities and differences between them. Designed for graduate students and scientists newly entering this field, this book provides a review not only of these explosions, but the detailed physical models used to explain them from the numerical techniques used to model neutrino transport and gamma-ray transport to the detailed nuclear physics behind the evolution of the collapse to the observations that have led to these three classes of explosions.

Download or read book Problems of Collapse and Numerical Relativity written by D. Bancel and published by Springer Science & Business Media. This book was released on 1984-08-31 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Research Workshop, Toulouse, France, November 7-11, 1983

Download or read book Numerical Experiments in Core collapse Supernova Hydrodynamics written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: PhD.

Download or read book Three Dimensional Core collapse Supernova Simulated Using a 15 M u2299 Progenitor written by and published by . This book was released on 2015 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have performed ab initio neutrino radiation hydrodynamics simulations in three and two spatial dimensions (3D and 2D) of core-collapse supernovae from the same 15 M⊙ progenitor through 440 ms after core bounce. Both 3D and 2D models achieve explosions; however, the onset of explosion (shock revival) is delayed by 1̃00 ms in 3D relative to the 2D counterpart and the growth of the diagnostic explosion energy is slower. This is consistent with previously reported 3D simulations utilizing iron-core progenitors with dense mantles. In the 1̃00 ms before the onset of explosion, diagnostics of neutrino heating and turbulent kinetic energy favor earlier explosion in 2D. During the delay, the angular scale of convective plumes reaching the shock surface grows and explosion in 3D is ultimately lead by a single, large-angle plume, giving the expanding shock a directional orientation not dissimilar from those imposed by axial symmetry in 2D simulations. Finally, we posit that shock revival and explosion in the 3D simulation may be delayed until sufficiently large plumes form, whereas such plumes form more rapidly in 2D, permitting earlier explosions.

Download or read book Supernovae Theory written by Anthea Francesca Fantina and published by . This book was released on 2010 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ln the framework of type II Supernovae theory, most of numerical simulations of the supernova core collapse and shock wave propagation fail to reproduce the observed explosion, because of both hydrodynamical phenomena and to some microphysical processes involved in the picture and not yet completely understood. The aim of this work is to investigate some microphysical aspects and to analyze their effects through hydrodynamical simulations. Among electro-weak processes occuring in core-collapse supernova, the most important one is the electron capture, crucial to determine the evolution of lepton fraction during the neutronization phase. It affects the efficiency of the bounce and the strength of the shock wave. Moreover, both the equation of state of supernova matter and electron capture rates in nuclei are modified by the nuclear effective mass in nuclei, induced by many-body correlations, and its temperature dependence. I will present a nuclear model aimed at studying the nuclear effective mass. We have included in a energy density functional approach a surface-peaked nuclear effective mass to mimic some effects beyond Hartree-Fock. I will then present the supernova models I have worked on, in a one-zone approximation, and in spherically symmetric one-dimensional approximation, Newtonian and General Relativistic. We will show that, introducing a temperature dependent effective mass into a one-zone and a one dimensional Newtonian code with neutrino transport, the deleptonization is reduced and has a non-negligible effect on the shock wave energetics. We will also present results obtained with the General Relativistic code with a multi-group treatment of neutrinos.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.

Download or read book Numerical Relativity written by Masaru Shibata and published by World Scientific. This book was released on 2015-11-05 with total page 844 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is composed of two parts: First part describes basics in numerical relativity, that is, the formulations and methods for a solution of Einstein's equation and general relativistic matter field equations. This part will be helpful for beginners of numerical relativity who would like to understand the content of numerical relativity and its background. The second part focuses on the application of numerical relativity. A wide variety of scientific numerical results are introduced focusing in particular on the merger of binary neutron stars and black holes.

Download or read book Effects of Non standard Neutrino Flavor Changing Interactions in Core Collapse Supernovae written by Philip Amanik and published by . This book was released on 2006 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-standard neutrino flavor changing interactions are included in the core collapse supernova model, and their effects on the model are investigated. Analytical and numerical results are presented. The predictions from a model that includes the new neutrino interactions are found to be different from the predictions of the original model. The non-standard interactions are predicted by some extensions to the standard model, but no such interactions have been discovered or proven to exist. An example of an interaction which comes from R-parity violating Supersymmetry is discussed in detail in Chapter 1. Reviews of nuclear physics and the supernova model are also given in this chapter. The cross sections for neutrino flavor changing scattering in vacuum with nuclei and free nucleons are given in Chapter 1. Corrections which account for neutrinos scattering with nuclei in the core medium are given in Chapter 2. Uncertainties in the equation of state and composition of nuclear matter at high density, and the impact of these uncertainties on neutrino scattering cross sections are discussed in Chapter 2 as well. Analytical estimates of flavor changing scattering rates are calculated in Chapter 1 and a qualitative discussion of the effects on the model is then offered. Results from a one-zone core collapse numerical simulation are presented in Chapter 2. A detailed discussion of the code, and equations which describe the core are included in this chapter. Chapter 3 outlines how to include these interactions in a full simulation with neutrino transport and hydrodynamics.