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Modeling Of Cosmic Ray Transport Processes
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Book Synopsis Modeling of Cosmic-Ray Transport Processes by :
Download or read book Modeling of Cosmic-Ray Transport Processes written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main task has been the development, testing, and data comparison of a global time dependent and three dimensional heliospheric transport code of galactic cosmic rays. While the code is based on current standard and established theory of solar modulation of galactic cosmic rays, it is far more computationally demanding than what a typical application oriented study may require. The purpose for developing such a code was to afford the group a fully three dimensional solar modulation model by which a computationally efficient parametric set of simulated data can reliably and efficiently be developed. This development should afford the group both qualitative and quantitative advantage in this regard and relative to modulation codes currently available to the group which tend to be rudimentary one dimensional codes. The report is in 4 sections: (1) description of the basic physical model the new three dimensional transport code is based upon, (2) numerical implementation and various algorithms of the code, (3) sample calculations and comparison to available data, and (4) direction and recommendations for future work.
Book Synopsis Nonlinear Cosmic Ray Diffusion Theories by : Andreas Shalchi
Download or read book Nonlinear Cosmic Ray Diffusion Theories written by Andreas Shalchi and published by Springer Science & Business Media. This book was released on 2009-06-04 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: If charged particles move through the interplanetary or interstellar medium, they interact with a large-scale magnetic ?eld such as the magnetic ?eld of the Sun or the Galactic magnetic ?eld. As these background ?elds are usually nearly constant in time and space, they can be approximated by a homogeneous ?eld. If there are no additional ?elds, the particle trajectory is a perfect helix along which the par- cle moves at a constant speed. In reality, however, there are turbulent electric and magnetic?elds dueto the interstellaror solar wind plasma. These ?elds lead to sc- tering of the cosmic rays parallel and perpendicular to the background ?eld. These scattering effects, which usually are of diffusive nature, can be described by s- tial diffusion coef?cients or, alternatively, by mean free paths. The knowledge of these parameters is essential for describing cosmic ray propagation as well as d- fusive shock acceleration. The latter process is responsible for the high cosmic ray energies that have been observed. The layout of this book is as follows. In Chap. 1, the general physical scenario is presented. We discuss fundamental processes such as cosmic ray propagation and acceleration in different systems such as the solar system or the interst- lar space. These processes are a consequence of the interaction between charged cosmic particles and an astrophysical plasma (turbulence). The properties of such plasmas are therefore the subject of Chap. 2.
Book Synopsis Cosmic Ray Astrophysics by : Reinhard Schlickeiser
Download or read book Cosmic Ray Astrophysics written by Reinhard Schlickeiser and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the first part, the book gives an up-to-date summary of the observational data. In the second part, it deals with the kinetic description of cosmic ray plasma. The underlying diffusion-convection transport equation, which governs the coupling between cosmic rays and the background plasma, is derived and analyzed in detail. In the third part, several applications of the solutions of the transport equation are presented and how key observations in cosmic ray physics can be accounted for is demonstrated.
Book Synopsis Transport Processes in Space Physics and Astrophysics by : Gary P. Zank
Download or read book Transport Processes in Space Physics and Astrophysics written by Gary P. Zank and published by Springer. This book was released on 2013-10-19 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: “Transport Processes in Space Physics and Astrophysics” is aimed at graduate level students to provide the necessary mathematical and physics background to understand the transport of gases, charged particle gases, energetic charged particles, turbulence, and radiation in an astrophysical and space physics context. Subjects emphasized in the work include collisional and collisionless processes in gases (neutral or plasma), analogous processes in turbulence fields and radiation fields, and allows for a simplified treatment of the statistical description of the system. A systematic study that addresses the common tools at a graduate level allows students to progress to a point where they can begin their research in a variety of fields within space physics and astrophysics. This book is for graduate students who expect to complete their research in an area of plasma space physics or plasma astrophysics. By providing a broad synthesis in several areas of transport theory and modeling, the work also benefits researchers in related fields by providing an overview that currently does not exist. For numerous interesting and challenging space physics and astrophysics problems, there is a need to describe the “long-term” behavior of systems governed by macroscopic laws and microscopic randomness. A random event has an outcome that is uncertain and unpredictable, yet the collective behavior of a system can be governed by well defined mathematical and physical principles. Examples of physical problems include the behavior of gases in the presence of microscopic inter-particle collisions, the evolution of a gas of charged protons and electrons (a plasma), the collective propagation of solar energetic particles or cosmic rays in a magnetically turbulent medium, the collective behavior of dust in an accretion disk subject to coagulation and destruction, the evolution of low-frequency magnetic field turbulence in the inhomogeneous solar wind, or the transport of photos in a partially ionized interstellar medium. This book provides graduate students with a unified introduction to the physics of collective phenomena or transport processes for gases (charged and uncharged), fields, and photons in a space physics or astrophysics context.
Book Synopsis Equations of Cosmic-Ray Transport with Distributed Acceleration by :
Download or read book Equations of Cosmic-Ray Transport with Distributed Acceleration written by and published by . This book was released on 1989 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The equations of cosmic-ray transport used in our galactic cosmic-ray propagation model are described. The equations include distributed acceleration terms associated with weak reacceleration of cosmic-ray ions in supernova remnants. Reacceleration may occur at any time during the diffusion of cosmic rays through the interstellar medium.
Book Synopsis Fractional Kinetics In Space: Anomalous Transport Models by : Vladimir V Uchaikin
Download or read book Fractional Kinetics In Space: Anomalous Transport Models written by Vladimir V Uchaikin and published by World Scientific. This book was released on 2017-12-12 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is first of its kind describing a new direction in modeling processes taking place in interplanetary and interstellar space (magnetic fields, plasma, cosmic rays, etc.). This method is based on a special mathematical analysis — fractional calculus. The reader will find in this book clear physical explanation of the fractional approach and will become familiar with basic rules in this calculus and main results obtained in frame of this approach. In spite of its profound subject, the book is not overloaded by mathematical details. It contains many illustrations, rich citation and remains accessible to a wide circle of physicists.This book is addressed to graduate and postgraduate students, young and mature researchers specializing in applications of fractional calculus, astrophysics, solar-terrestrial science and physics of cosmic rays.
Book Synopsis Cosmic-ray Transport and Signatures in Their Local Environment by : Vasundhara Shaw
Download or read book Cosmic-ray Transport and Signatures in Their Local Environment written by Vasundhara Shaw and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin and structure of magnetic fields in the Galaxy are largely unknown. What is known is that they are essential for several astrophysical processes, in particular the propagation of cosmic rays. Our ability to describe the propagation of cosmic rays through the Galaxy is severely limited by the lack of observational data needed to probe the structure of the Galactic magnetic field on many different length scales. This is particularly true for modelling the propagation of cosmic rays into the Galactic halo, where our knowledge of the magnetic field is particularly poor. In the last decade, observations of the Galactic halo in different frequency regimes have revealed the existence of out-of-plane bubble emission in the Galactic halo. In gamma rays these bubbles have been termed Fermi bubbles with a radial extent of ≈ 3 kpc and an azimuthal height of ≈ 6 kpc. The radio counterparts of the Fermi bubbles were seen by both the S-PASS telescopes and the Planck satellite, and showed a clear spatial overlap. [...].
Book Synopsis Study of Non-thermal Emission from Supernova Remnants and Cosmic Ray Injection in the Milky Way Using the Fermi Large Area Telescope by : Shiu Hang Lee
Download or read book Study of Non-thermal Emission from Supernova Remnants and Cosmic Ray Injection in the Milky Way Using the Fermi Large Area Telescope written by Shiu Hang Lee and published by Stanford University. This book was released on 2011 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supernova remnants (SNRs) are the only class of sources known in our Galaxy capable of providing the energy necessary to power the bulk of the Galactic cosmic-rays (CRs) below the `knee' (~ 3 PeV). They are observable across the entire frequency spectrum from radio to TeV gamma-rays, and are known to exhibit a rich variety of complex morphologies in multi-wavelength. Non-thermal emissions from SNRs in X-ray and gamma-ray arise from interaction between particles accelerated by the SNR blast wave and the surrounding medium, and are hence one of the most useful probe for the Galactic CR production process. In this thesis, we will try to obtain a fuller understanding of the origin of Galactic CRs through studying non-thermal emissions from SNRs and modelling CR injection from their astrophysical accelerators. In the first part of the thesis, we will develop a robust tool to simulate time and space-resolved broadband emission from young shell-type SNRs using coupled hydrodynamic and diffusive shock acceleration (DSA) calculations. Usually, the DSA process is expected to be highly non-linear for young SNRs due to a number of postulated coupling phenomena, which leads to the inter-correlation of the emission spectra and morphology at different wavelengths. Therefore, to gain the full picture, it is important to combine multi-wavelength observations and the relevant physical processes into a self-consistent and flexible calculation framework. By taking into account particle transport, escape, interaction and various radiative processes, our tool can predict photon emissivity in full three-dimension and multi-wavelength for any given SNR model and surrounding environment, such as in the presence of a nearby molecular cloud. Through illustrations using a few typical models for Type Ia SNR, we will demonstrate its capability of calculating results directly comparable to observations, as well as to pinpoint the gamma-ray emission mechanism, namely the leptonic and hadronic scenarios. In the second part, we will study the gamma-ray emission from a middle-aged SNR IC 443 (G189.1+3.0) using the Fermi Large Area Telescope (LAT). IC 443 has been extensively studied in the past few decades through radio to TeV gamma-ray, but high quality data in the sub-GeV to sub-TeV band, the most crucial window for constraining the origin of the high-energy emission, has still been missing. We will fill in this gap by analyzing LAT data from 200 MeV to 50 GeV using the 1st year of LAT data. Equipped with the high photon statistics available, and the excellent resolution, sensitivity and low background rate of LAT, we are able to probe the gamma-ray emission from IC 443 with minimal confusion with the backgrounds. We discovered spatially extended emission from IC 443 in the 1 - 50 GeV band for the first time, which eliminates the pulsar wind nebula (PWN) as the dominating gamma-ray emitter. We found good spatial correlation of the GeV mission with the TeV source recently detected by VERITAS, as well as a known group of ambient and shocked molecular clouds (MC). The sub-GeV to TeV broadband spectrum can be described by a power-law with a smooth break at a few GeV, the same feature also observed from several other LAT-detected middle-aged SNRs interacting with MCs. We will argue that the gamma-ray emission is most naturally explained by a neutral pion decay dominated origin, and the leptonic scenarios are disfavored. Finally, we will also discuss the major discoveries from LAT observations of other gamma-ray bright Galactic SNRs during the first 2 years of operation of Fermi. In the last part, we will construct a model of Galactic CR injection using constraints from most recent GeV and TeV observation data and CR measurements, which can provide a natural explanation for the enhanced positron flux above 10 GeV recently observed by PAMELA as compared to previous measurements. Without making speculation on `additional' positron contribution from any special nearby objects or resorting to exotic phenomena, we will look at a steady-state picture of our Galaxy in which the ensembles of SNRs and PWNe steadily inject CRs into the interstellar space. Using the GALPROP CR propagation code, the CR spectra and ratios at Earth are calculated and compared with data. Without tweaking the model parameters specifically to fit the positron data other than using observation and astrophysics-based assumptions, we will show that this steady-state model can satisfactorily reproduce the positron enhancement and other CR measurement results. Assisted by recent observations of middle-aged SNRs interacting with MCs by Fermi LAT, we are also able to set an upper-limit on the total number of these systems residing in our Galaxy. Finally, using this consistent model, we will estimate the energy budgets of the major species of Galactic CRs.
Book Synopsis Cosmic Ray Interactions, Propagation, and Acceleration in Space Plasmas by : Lev Dorman
Download or read book Cosmic Ray Interactions, Propagation, and Acceleration in Space Plasmas written by Lev Dorman and published by Springer Science & Business Media. This book was released on 2006-09-02 with total page 877 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1 briefly describes the main properties of space plasmas and primary CR. Chapter 2 considers the problem of CR propagation in space plasmas described by the kinetic equation and different types of diffusion approximations. Chapter 3 is devoted to CR non-linear effects in space plasmas caused by CR pressure and CR kinetic stream instabilities with the generation of Alfvèn turbulence. In Chapter 4 different processes of CR acceleration in space plasmas are considered. The book ends with a list providing more than 1,300 full references, a discussion on future developments and unsolved problems, as well as Object and Author indexes.
Book Synopsis An Anisotropic Model for Galactic Cosmic Ray Transport by : Iris Gebauer
Download or read book An Anisotropic Model for Galactic Cosmic Ray Transport written by Iris Gebauer and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2010-04 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin of cosmic rays has been intriguing scientists since 1912 when Victor Hess carried out his famous balloon flight to measure the ionization rate in the upper atmosphere. Since then cosmic ray physics brings together physicists from a variety of different fields such as astrophysics, cosmology and particle physics. The increasing amount of available data has enabled us to successfully describe the transport of Galactic cosmic rays in a simple isotropic diffusion picture. However, recent data from the ROSAT satellite indicate that the Milky Way launches significant Galactic winds. Such wind speeds cannot be explained in the context of isotropic diffusion models. In this work an anisotropic transport model, which allows for ROSAT compatible wind velocities and still meets all the constraints from primary and secondary cosmic rays, cosmic clocks and gamma rays, is introduced. Such a model predicts a large bulge over disk ratio in the positron annihilation signal, in agreement with the INTEGRAL observations. Furthermore, the implications of anisotropic Galactic cosmic ray transport for indirect dark matter searches in charged cosmic rays and diffuse gamma rays are discussed.
Book Synopsis Elementary Processes for Cosmic Ray Astrophysics by : Vitaliĭ Lazarevich Ginzburg
Download or read book Elementary Processes for Cosmic Ray Astrophysics written by Vitaliĭ Lazarevich Ginzburg and published by . This book was released on 1969 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Semiempirical Fragmentation Models on Galactic Cosmic Ray Transport Calculations with Hydrogen Target by : Judy L. Shinn
Download or read book Semiempirical Fragmentation Models on Galactic Cosmic Ray Transport Calculations with Hydrogen Target written by Judy L. Shinn and published by . This book was released on 1993 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Cosmic Ray Diffusion by : Thomas Joseph Birmingham
Download or read book Cosmic Ray Diffusion written by Thomas Joseph Birmingham and published by . This book was released on 1975 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Topics discussed and summarized are: cosmic ray measurements as related to diffusion theory; quasi-linear theory, nonlinear theory, and computer simulation of cosmic ray pitch-angle diffusion; and magnetic field fluctuation measurements as related to diffusion theory.
Book Synopsis The Influence of Cosmic Ray Transport on the Stability of Interstellar Gas by : Evan Mitchell Heintz
Download or read book The Influence of Cosmic Ray Transport on the Stability of Interstellar Gas written by Evan Mitchell Heintz and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmic rays play a major role in the stability and evolution of galaxies. While they have a fairly small density inside galaxies, their energy density is comparable to the thermal gas and magnetic fields. We now believe that cosmic rays play a major role in galactic and interstellar dynamics, including helping to drive galactic outflows, modify the galaxy's interstellar chemistry, and form large-scale structures. To understand the process of how cosmic rays do this, their microscale interactions with the gas and magnetic fields must be accurate so that their macroscale effects can reproduce observations. Our work in this thesis specifically focuses on how different models of cosmic ray transport change these interactions and their effects. Through the combined approach of analytical solutions and numerical simulations, this thesis aims to better understand how cosmic ray transport affects the stability of the interstellar medium and drive galactic outflows. We begin in Chapter 2 with a linear stability analysis of the Parker instability, a Rayleigh-Taylor like instability with the thermal gas supported against gravity by magnetic fields and cosmic rays. We model three different cosmic ray transport models and find that the model where cosmic rays stream relative to the thermal gas most greatly enhances the instability due to the heating of the thermal gas by cosmic rays scattering off of magnetic fluctuations. We continue with the Parker instability in Chapter 3 where we add radiative cooling to the system and then run numerical simulations with a smooth gravitational potential in 2D and 3D to better understand the nonlinear evolution of the instability in a more realistic environment. When radiative cooling is added, we find it enhances the instability when cosmic rays are locked to the thermal gas while it dampens the instability when cosmic ray streaming is the primary mode of transport. In our MHD simulations, we find that both cosmic ray diffusion and streaming enhance the growth of the instability due to the motion of cosmic rays out of the compressive pockets of gas in the valleys of the magnetic field. While the instability growth seems similar, however, the two transport models result in quite different phase structures of the gas, especially at the top of the Parker loops where streaming cosmic rays heat the gas. We then explore the idea of a cosmic ray Eddington limit in Chapter 4. This theory supposes that cosmic rays, through their own pressure gradient, may be able to overcome hydrostatic equilibrium and launch an outflow if star formation is vigorous enough in that galaxy. For five different galaxies and many different transport models, we find that a cosmic ray Eddington limit does exist. However, the Eddington limit often requires gas densities and/or star formation rates that are far different from typical values for galaxies. Therefore, we conclude that it is unlikely that cosmic rays themselves can reach this Eddington limit and drive a galactic wind. We finally conclude in Chapter 5 with a summary of our results and a short discussion on the future research that could be done based around our conclusions.
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1991 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Anisotropic Model for Galactic Cosmic Ray Transport and Its Implications for Indirect Dark Matter Searches by : Iris Gebauer
Download or read book An Anisotropic Model for Galactic Cosmic Ray Transport and Its Implications for Indirect Dark Matter Searches written by Iris Gebauer and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Relationship Between Galactic Cosmic Rays and Solar Wind by : Grace Dominic Ihongo
Download or read book The Relationship Between Galactic Cosmic Rays and Solar Wind written by Grace Dominic Ihongo and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
