Intergalactic Magnetic Field and Arrival Direction of Ultra-High-Energy Protons (2009)
Ryu, Dongsu, Das, Santabrata, Kang, Hyesung
We studied how the intergalactic magnetic field (IGMF) affects the propagation of super-GZK protons that originate from extragalactic sources within the local GZK sphere. Toward this end, we set up...
Estimation of Magnetic Field Strength in the Turbulent Warm Ionized Medium (2009)
Wu, Qingwen, Kim, Jongsoo, Ryu, Dongsu, Cho, Jungyeon, Alexander, Paul
We studied Faraday rotation measure (RM) in turbulent media with the rms Mach number of unity, using isothermal, magnetohydrodynamic turbulence simulations. Four cases with different values of...
Characteristic Lengths of Magnetic Field in Magnetohydrodynamic Turbulence (2009)
In the framework of turbulence dynamo, flow motions amplify a weak seed magnetic field through the stretching of field lines. Although the amplification process has been a topic of active research,...
Ryu, Dongsu, Kang, Hyesung, Das, Santabrata
Ultrahigh energy cosmic rays (UHECRs) are believed to originate from astrophysical sources, which should trace the large scale structure (LSS) of the universe. On the other hand, the magnetic field...
Self-Similar Evolution of Cosmic-Ray Modified Shocks: The Cosmic-Ray Spectrum (2009)
Kang, Hyesung, Ryu, Dongsu, Jones, T. W.
We use kinetic simulations of diffusive shock acceleration (DSA) to study the time-dependent evolution of plane, quasi-parallel, cosmic-ray (CR) modified shocks. Thermal leakage injection of low...
Effects of Fluid Composition on Spherical Flows around Black Holes (2008)
Chattopadhyay, Indranil, Ryu, Dongsu
Steady, spherically symmetric, adiabatic accretion and wind flows around non-rotating black holes were studied for fully ionized, multi-component fluids, which are described by a relativistic...
Shock Waves in the Large-Scale Structure of the Universe (2008)
Cosmological shock waves are induced during hierarchical formation of large-scale structure in the universe. Like most astrophysical shocks, they are collisionless, since they form in the tenuous...
Turbulence and Magnetic Fields in the Large Scale Structure of the Universe (2008)
Ryu, Dongsu, Kang, Hyesung, Cho, Jungyeon, Das, Santabrata
The nature and origin of turbulence and magnetic fields in the intergalactic space are important problems that are yet to be understood. We propose a scenario in which turbulent flow motions are...
Abstract. Starting with the meaning of the word quality, diverse concepts connoted by the term are examined. Instead of a bathtub curve, the desirable shape of a failure rate covering the entire life...
COSMIC RAYS AND THEIR RADIATIVE PROCESSES IN NUMERICAL COSMOLOGY (2008)
Dongsu Ryu, Francesco Miniati, Tom W. Jones, Hyesung Kang
para calcular, de manera simplificada, la aceleración y el transporte de los rayos cósmicos. La rutina fue diseñada para seguir de manera explícita la aceleración difusiva en choques y la...
Propagation of UHE Protons through Magnetized Cosmic Web (2008)
Das, Santabrata, Kang, Hyesung, Ryu, Dongsu, Cho, Jungyeon
If ultra-high-energy cosmic rays (UHECRs) originate from extragalactic sources, understanding the propagation of charged particles through the magnetized large scale structure (LSS) of the universe...
Robert A. Laing, Katherine M. Blundell, I. L. Tregillis, T. W. Jones, Dongsu Ryu
Abstract. We perform a series of so-called \synthetic observations" on a set of 3D MHD jet simulations which explicitly include energydependent transport of relativistic electrons, as...
3D MHD Simulations of Radio Galaxies Including Nonthermal Electron Transport (2007)
Robert A. Laing, Katherine M. Blundell, T. W. Jones, I. L. Tregillis, Dongsu Ryu
Abstract. We report on an eort to study the connections between dynamics in simulated radio galaxy plasma ows and the properties of nonthermal electron populations carried in those ows. To do this we...
The Parker Instability under a Linear Gravity (2007)
Jongsoo Kim, Seung Soo Hong, Dongsu Ryu
A linear stability analysis has been done to a magnetized disk under a linear gravity. We have reduced the linearized perturbation equations to a second-order differential equation which resembles...
The Protogalactic Origin for Cosmic Magnetic Fields (2007)
Russell M. Kulsrud, Renyue Cen, Jeremiah P. Ostriker, Dongsu Ryu
It is demonstrated that strong magnetic fields are produced from a zero initial magnetic field during the pregalactic era, when galaxies are first forming. Their development proceeds in three phases....
Propagation of UHE protons through a magnetized large scale structure (2007)
Kang, Hyesung, Das, Santabrata, Ryu, Dongsu, Cho, Jungyeon
The propagation of UHECRs is affected by the intergalactic magnetic fields that were produced during the course of the large scale structure formation of the universe. We adopt a novel model where...
The X-ray Pulse Profile of BG CMi (2007)
Choi, Chul-Sung, Dotani, Tadayasu, Kim, Yonggi, Ryu, Dongsu
We present an analysis of the X-ray data of a magnetic cataclysmic variable, BG CMi, obtained with ROSAT in March 1992 and with ASCA in April 1996. We show that four peaks clearly exist in the X-ray...
Kang, Hyesung, Ryu, Dongsu, Cen, Renyue, Ostriker, J. P.
Cosmological shock waves result from supersonic flow motions induced by hierarchical clustering of nonlinear structures in the universe. These shocks govern the nature of cosmic plasma through...
Hydrodynamic Interactions of Relativistic Extragalactic Jets with Dense Clouds (2006)
Choi, Eunwoo, Wiita, Paul J., Ryu, Dongsu
We have studied three-dimensional hydrodynamic interactions of relativistic extragalactic jets with two-phase ambient media. These jets propagate through a denser homogeneous gas and then impact...
Cosmic rays and their radiative processes in numerical cosmology (2006)
Dongsu Ryu, Francesco Miniati, Tom W. Jones, Hyesung Kang
Cosmic rays and their radiative processes in numerical cosmology
Three-dimensional simulations of the parker instability in a uniformly-rotating disk (2006)
Dongsu Ryu, T. W. Jones, Jongsoo Kim
Three-dimensional simulations of the parker instability in a uniformly-rotating disk
Equation of State in Numerical Relativistic Hydrodynamics (2006)
Ryu, Dongsu, Chattopadhyay, Indranil, Choi, Eunwoo
Relativistic temperature of gas raises the issue of the equation of state (EoS) in relativistic hydrodynamics. We study the EoS for numerical relativistic hydrodynamics, and propose a new EoS that is...
Baek, Chang Hyun, Ryu, Dongsu, Kang, Hyesung, Kim, Jongsoo
Thermal-gravitational instability (TGI) is studied in the protogalactic environment. We extend our previous work, where we found that dense clumps first form out of hot background gas by thermal...
Shapiro, Paul R., Ahn, Kyungjin, Alvarez, Marcelo A., Iliev, Ilian T., Martel, Hugo, Ryu, Dongsu
The H atoms inside minihalos (i.e. halos with virial temperatures T_vir < 10^4 K, in the mass range roughly from 10^4 M_sun to 10^8 M_sun) during the cosmic dark ages in a LambdaCDM universe produce...
Ahn, Kyungjin, Shapiro, Paul R., Alvarez, Marcelo A., Iliev, Ilian T., Martel, Hugo, Ryu, Dongsu
The H atoms inside minihalos (i.e. halos with virial temperatures T_vir < 10^4 K, in the mass range roughly from 10^4 M_sun to 10^8 M_sun) during the cosmic dark ages in a LCDM universe produce a...
Molecular cloud evolution. I. Molecular cloud and thin CNM sheet formation (2005)
Vazquez-Semadeni, Enrique, Ryu, Dongsu, Passot, Thierry, Gonzalez, Ricardo F., Gazol, Adriana
We discuss molecular cloud formation by large-scale supersonic compressions in the diffuse warm neutral medium (WNM). Initially, a shocked layer forms, and within it, a thin cold layer. An analytical...
3D Simulations of MHD Jet Propagation Through Uniform and Stratified External Environments (2005)
O'Neill, S. M., Tregillis, I. L., Jones, T. W., Ryu, Dongsu
We present a set of high-resolution 3D MHD simulations of steady light, supersonic jets, exploring the influence of jet Mach number and the ambient medium on jet propagation and energy deposition...
Density Power Spectrum of Compressible Hydrodynamic Turbulent Flows (2005)
Turbulent flows are ubiquitous in astrophysical environments, and understanding density structures and their statistics in turbulent media is of great importance in astrophysics. In this paper, we...
Numerical Relativistic Hydrodynamics Based on the Total Variation Diminishing Scheme (2005)
This paper describes a multidimensional hydrodynamic code which can be used for studies of relativistic astrophysical flows. The code solves the special relativistic hydrodynamic equations as a...
Baek, Chang Hyun, Kang, Hyesung, Kim, Jongsoo, Ryu, Dongsu
We study thermal-gravitational instability in simplified models for protogalactic halos using three-dimensional hydrodynamic simulations. The simulations followed the evolution of gas with radiative...
Shock-Heated Gas in the Large Scale Structure of the Universe (2004)
Kang, Hyesung, Ryu, Dongsu, Cen, Renyue, Song, Doojong
Cosmological shock waves play a major role in heating baryonic gas in the large scale structure of the universe. In this contribution we study the shock-heated gas in connection with shocks...
Synthetic Observations of Simulated Radio Galaxies I: Radio and X-ray Analysis (2003)
Tregillis, I. L., Jones, T. W., Ryu, Dongsu
We present an extensive synthetic observational analysis of numerically- simulated radio galaxies designed to explore the effectiveness of conventional observational analyses at recovering physical...
Cosmological Shock Waves and Their Role in the Large Scale Structure of the Universe (2003)
Ryu, Dongsu, Kang, Hyesung, Hallman, Eric, Jones, T. W.
We study the properties of cosmological shock waves identified in high-resolution, N-body/hydrodynamic simulations of a $\Lambda$CDM universe and their role on thermalization of gas and acceleration...
Numerical Study of Compressible Magnetohydrodynamic Turbulence in Two Dimensions (2003)
Lee, Hyesook, Ryu, Dongsu, Kim, Jongsoo, Jones, T. W., Balsara, Dinshaw
We have studied forced turbulence of compressible magnetohydrodynamic (MHD) flows through two-dimensional simulations with different numerical resolutions. First, hydrodynamic turbulence with Mach...
The Effect of Cosmic Ray Diffusion on the Parker Instability (2003)
Ryu, Dongsu, Kim, Jongsoo, Hong, Seung Soo, Jones, T. W.
The Parker instability, which has been considered as a process governing the structure of the interstellar medium, is induced by the buoyancy of magnetic field and cosmic rays. In previous studies,...
Structure shocks as a source of cosmic rays in clusters (2003)
Jones, T. W., Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Hallmann, Eric J.
Clusters of Galaxies: Shock Waves and Cosmic Rays (2002)
Recent observations of galaxy clusters in radio and X-ray indicate that cosmic rays and magnetic fields may be energetically important in the intracluster medium. According to the estimates based on...
Cosmic Rays in Clusters of Galaxies (2002)
Biermann, Peter L., Enßlin, Torsten A., Kang, Hyesung, Lee, Hyesook, Ryu, Dongsu
We argue that clusters of galaxies have an intergalactic medium, which is permeated by strong magnetic fields and also has a contribution of pressure from cosmic rays. These two components of total...
Two-Dimensional Axisymmetric Collapse of Thermally Unstable Primordial Clouds (2002)
Baek, Chang Hyun, Kang, Hyesung, Ryu, Dongsu
We have performed two-dimensional hydrodynamic simulations of the collapse of isolated axisymmetric clouds condensing via radiative cooling in a primordial background gas. In order to study the...
Structure Shocks as a Source of Cosmic Rays in Clusters (2002)
Jones, T. W., Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Hallman, Eric J.
Shocks are a ubiquitous consequence of cosmic structure formation, and they play an essential role in heating galaxy cluster media. Virtually all of the gas in clusters has been processed by one or...
The Effect of the Random Magnetic Field Component on the Parker Instability (2001)
The Parker instability is considered to play important roles in the evolution of the interstellar medium. Most studies on the development of the instability so far have been based on an initial...
Miniati, Francesco, Jones, T. W., Kang, Hyesung, Ryu, Dongsu
We study the generation and distribution of high energy electrons in cosmic environment and their observational consequences by carrying out the first cosmological simulation that includes directly...
Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Jones, T. W.
We investigate the production of cosmic ray (CR) protons at cosmological shocks by performing, for the first time, numerical simulations of large scale structure formation that include directly the...
Tregillis, I. L., Jones, T. W., Ryu, Dongsu
We present the first three-dimensional MHD radio galaxy simulations that explicitly model transport of relativistic electrons, including diffusive acceleration at shocks as well as radiative and...
Three-dimensional Simulations of the Parker Instability in a Uniformly-rotating Disk (2001)
Kim, Jongsoo, Ryu, Dongsu, Jones, T. W.
We investigate the effects of rotation on the evolution of the Parker instability in an exponentially-stratified and uniformly-rotating magnetized gas disk by carrying out three-dimensional numerical...
3D MHD Simulations of Radio Galaxies Including Nonthermal Electron Transport (2000)
Jones, T. W., Tregillis, I. L., Ryu, Dongsu
We report on an effort to study the connections between dynamics in simulated radio galaxy plasma flows and the properties of nonthermal electron populations carried in those flows. To do this we...
Tregillis, I. L., Jones, T. W., Ryu, Dongsu
We perform a series of so-called ``synthetic observations'' on a set of 3D MHD jet simulations which explicitly include energy-dependent transport of relativistic electrons, as described in the...
Winds and Shocks in Galaxy Clusters: Shock Acceleration on an Intergalactic Scale (2000)
Jones, T. W., Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung
We review the possible roles of large scale shocks as particle accelerators in clusters of galaxies. Recent observational and theoretical work has suggested that high energy charged particles may...
Formation of Proto-Globular Cluster Clouds by Thermal Instability (2000)
Kang, Hyesung, Lake, George, Ryu, Dongsu
Many models of globular cluster formation assume the presence of cold dense clouds in early universe. Here we re-examine the Fall & Rees (1985) model for formation of proto-globular cluster clouds...
Ryu, Dongsu, Jones, T. W., Frank, Adam
We investigate through high resolution 3D simulations the nonlinear evolution of compressible magnetohydrodynamic flows subject to the Kelvin-Helmholtz instability. We confirm in 3D flows the...
The Parker Instability in a Thick Gaseous Disk II: Numerical Simulations in 2D (2000)
Santillan, Alfredo, Kim, Jongsoo, Franco, Jose, Martos, Marco, Hong, S. S., Ryu, Dongsu
We present 2D, ideal-MHD numerical simulations of the Parker instability in a multi-component warm disk model. The calculations were done using two numerical codes with different algorithms, TVD and...
3-D MHD Numerical Simulations of Cloud-Wind Interactions (2000)
Gregori, G., Miniati, Francesco, Ryu, Dongsu, Jones, T. W.
We present results from three-dimensional (3-D) numerical simulations investigating the magnetohydrodynamics of cloud-wind interactions. The initial cloud is spherical while the magnetic field is...
Properties of Cosmic Shock Waves in Large Scale Structure Formation (2000)
Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Jones, T. W., Cen, Renyue, Ostriker, Jeremiah P.
We have examined the properties of shock waves in simulations of large scale structure formation for two cosmological scenarios (a SCDM and a LCDM with Omega =1). Large-scale shocks result from...
Miniati, Francesco, Ryu, Dongsu, Jones, T. W., Kang, Hyesung
We investigate the dynamical importance of a newly recognized possible source of significant feedback generated during structure formation; namely cosmic ray (CR) pressure. We present evidence for...
Cosmic rays and their radiative processes in numerical cosmology (2000)
Jones , Tom W., Kang , Hyesung, Miniati , Francesco, Ryu , Dongsu
A cosmological hydrodynamic code is described, which includes a routine to compute cosmic ray acceleration and transport in a simpli ed way. The routine was designed to follow explicitly di usive...
Three-Dimensional Simulations Of The Parker Instability In A Uniformly-Rotating Disk (2000)
Jongsoo Kim, Dongsu Ryu, T. W. Jones
We investigate the nonlinear eects of uniform rotation on the Parker instability in an exponentially-strati ed disk through high-resolution simulations. During the linear stage, the speed of gas...
Three-Dimensional Simulations Of The Parker Instability In A Uniformly-Rotating Disk (2000)
Jongsoo Kim, Dongsu Ryu, T. W. Jones
We investigate the nonlinear e#ects of uniform rotation on the Parker instability in an exponentially-stratified disk through high-resolution simulations. During the linear stage, the speed of gas...
Cosmic Rays and Their Radiative Processes in Numerical Cosmology (1999)
Ryu, Dongsu, Miniati, Francesco, Jones, Tom W., Kang, Hyesung
A cosmological hydrodynamic code is described, which includes a routine to compute cosmic ray acceleration and transport in a simplified way. The routine was designed to follow explicitly diffusive...
Three-Dimensional Simulations of the Parker Instability in a Uniformly-rotating Disk (1999)
Kim, Jongsoo, Ryu, Dongsu, Jones, T. W.
We investigate the nonlinear effects of uniform rotation on the Parker instability in an exponentially-stratified disk through high-resolution simulations. During the linear stage, the speed of gas...
Enhanced Cloud Disruption by Magnetic Field Interaction (1999)
Gregori, G., Miniati, Francesco, Ryu, Dongsu, Jones, T. W.
We present results from the first three-dimensional numerical simulations of moderately supersonic cloud motion through a tenuous, magnetized medium. We show that the interaction of the cloud with a...
The MHD Kelvin-Helmholtz Instability III: The Role of Sheared Magnetic Field in Planar Flows (1999)
Jeong, Hyunju, Ryu, Dongsu, Jones, T. W., Frank, Adam
We have carried out simulations of the nonlinear evolution of the magnetohydrodynamic (MHD) Kelvin-Helmholtz (KH) instability for compressible fluids in $2\frac{1}{2}$-dimensions, extending our...
Jones, T. W., Tregillis, I. L., Ryu, Dongsu
We have developed an economical, effective numerical scheme for cosmic-ray transport suitable for treatment of electrons up to a few hundreds of GeV in multidimensional simulations of radio galaxies....
Tregillis, I. L., Jones, T. W., Ryu, Dongsu, Park, Charles
We have applied an effective numerical scheme for cosmic-ray transport to 3D MHD simulations of jet flow in radio galaxies (see the companion paper by Jones et al. 1999). The marriage of relativistic...
Large Cosmic Shock Waves as Sites for Particle Acceleration (1999)
Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Jones, T. W.
The properties of cosmic shock waves are studied through numerical simulations in two cosmological scenarios (SCDM and LCDM). The scaling relations for the average radius and velocity associated with...
On the Exchange of Kinetic and Magnetic Energy Between Clouds and the Interstellar Medium (1999)
Miniati, Francesco, Jones, T. W., Ryu, Dongsu
We investigate, through 2D MHD numerical simulations, the interaction of a uniform magnetic field oblique to a moving interstellar cloud. In particular we explore the transformation of cloud kinetic...
A Multi-dimensional Code for Isothermal Magnetohydrodynamic Flows in Astrophysics (1998)
Kim, Jongsoo, Ryu, Dongsu, Jones, T. W., Hong, S. S.
We present a multi-dimensional numerical code to solve isothermal magnetohydrodynamic (IMHD) equations for use in modeling astrophysical flows. First, we have built a one-dimensional code which is...
Jones, T. W., Ryu, Dongsu, Engel, Andrew
We introduce a simple and economical but effective method for including relativistic electron transport in multi-dimensional simulations of radio galaxies. The method is designed to follow explicitly...
Three-Dimensional Evolution of the Parker Instability under a Uniform Gravity (1998)
Kim, Jongsoo, Hong, S. S., Ryu, Dongsu, Jones, T. W.
Using an isothermal MHD code, we have performed three-dimensional, high-resolution simulations of the Parker instability. The initial equilibrium system is composed of exponentially-decreasing...
Magnetohydrodynamics of Cloud Collisions in a Multi-phase Interstellar Medium (1998)
Miniati, Francesco, Ryu, Dongsu, Ferrara, Andrea, Jones, T. W.
We extend previous studies of the physics of interstellar cloud collisions by beginning investigation of the role of magnetic fields through 2D magnetohydrodynamic (MHD) numerical simulations. We...
A Divergence-Free Upwind Code for Multidimensional Magnetohydrodynamic Flows (1998)
Ryu, Dongsu, Miniati, Francesco, Jones, T. W., Frank, Adam
A description is given for preserving ${\bmsy\nabla}\cdot{\vec B}=0$ in a magnetohydrodynamic (MHD) code that employs the upwind, Total Variation Diminishing (TVD) scheme and the Strang-type operator...
Where's the Doughnut? LBV bubbles and Aspherical Fast Winds (1998)
Frank, Adam, Ryu, Dongsu, Davidson, Kris
In this paper we address the issue of the origin of LBV bipolar bubbles. Previous studies have explained the shapes of LBV nebulae, such as $\eta$ Car, by invoking the interaction of an isotropic...
Cosmic Magnetic Fields in Large Scale Filaments and Sheets (1998)
Ryu, Dongsu, Kang, Hyesung, Biermann, Peter L.
We consider the possibility that cosmic magnetic field, instead of being uniformly distributed, is strongly correlated with the large scale structure of the universe. Then, the observed rotational...
Baryonic fraction in the cold plus hot dark matter universe (1997)
We report a study to constrain the fraction of baryonic matter in the cold plus hot dark matter (CHDM) universe by numerical simulations which include the hydrodynamics of baryonic matter as well as...
The supergalactic structure and the origin of the highest energy cosmic rays (1997)
Biermann, Peter L., Kang, Hyesung, Ryu, Dongsu
The recent discoveries of several reliable events of high energy cosmic rays at an energy above 10^20 eV raise questions about their path through the nearby universe. The two analyses of the Haverah...
Cosmic Structure of Magnetic Fields (1997)
Biermann, Peter L., Kang, Hyesung, Rachen, Joerg P., Ryu, Dongsu
The simulations of the formation of cosmological structure allows to determine the spatial inhomogeneity of cosmic magnetic fields. Such simulations, however, do not give an absolute number for the...
Hydrodynamics of Cloud Collisions in 2D: The Fate of Clouds in a Multi-phase Medium (1997)
Miniati, Francesco, Jones, T. W., Ferrara, Andrea, Ryu, Dongsu
We have studied head-on collisions between equal-mass, mildly supersonic (Mach number 1.5) HI clouds, in a standard Two-phase ISM (T_cl = 74 K, n_cl = 22 cm^-3, \chi = 100). We explore the role of...
The Parker Instability under a Linear Gravity (1997)
Kim, Jongsoo, Hong, Seung Soo, Ryu, Dongsu
A linear stability analysis has been done to a magnetized disk under a linear gravity. We have reduced the linearized perturbation equations to a second-order differential equation which resembles...
Numerical Simulations of Rotating Accretion Flows near a Black Hole (1997)
Ryu, Dongsu, Chakrabarti, Sandip K.
We present time-dependent solutions of thin, supersonic accretion flows near a black hole and compare them with analytical solutions. Such flows of inviscid, adiabatic gas are characterized by the...
Cosmic Shock Waves on Large Scales of the Universe (1997)
In the standard theory of the large scale structure formation, matter accretes onto high density perturbations via gravitational instability. Collisionless dark matter forms caustics around such...
The MHD Kelvin-Helmholtz Instability II: The Roles of Weak and Oblique Fields in Planar Flows (1997)
Jones, T. W., Gaalaas, Joseph B., Ryu, Dongsu, Frank, Adam
We have carried out high resolution MHD simulations of the nonlinear evolution of Kelvin-Helmholtz unstable flows in 2 1/2 dimensions. The modeled flows and fields were initially uniform except for a...
The Protogalactic Origin for Cosmic Magnetic Fields (1996)
Kulsrud, Russell M., Cen, Renyue, Ostriker, Jeremiah P., Ryu, Dongsu
It is demonstrated that strong magnetic fields are produced from a zero initial magnetic field during the pregalactic era, when galaxies are first forming. Their development proceeds in three phases....
Zero Energy Rotating Accretion Flows near a Black Hole (1996)
Ryu, Dongsu, Chakrabarti, Sandip K., Molteni, Diego
We characterize the nature of thin, axisymmetric, inviscid, accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using...
The Magnetohydrodynamics of Supersonic Gas Clouds: MHD Cosmic Bullets and Wind-Swept Clumps (1996)
Jones, T. W., Ryu, Dongsu, Tregillis, I. L.
We report an extensive set of two-dimensional MHD simulations exploring the role and evolution of magnetic fields in the dynamics of supersonic plasma clumps. We examine the influence of both ambient...
Molteni, Diego, Ryu, Dongsu, Chakrabarti, Sandip K.
We compare the results of numerical simulations of thin and quasi-spherical (thick) accretion flows with existing analytical solutions. We use a Lagrangian code based on the Smooth Particle...
Cosmic Shock Waves on Large Scales of the Universe (1996)
In the standard theory of the large scale structure formation, matter accretes onto high density perturbations via gravitational instability. Collisionless dark matter forms caustics around such...
Parker Instability: Continuum vs. Discrete Solutions (1996)
Jongsoo Kim, S. S. Hong, Dongsu Ryu
Since the pioneering work of Parker (1966), there have been many studies on the stability of a magnetized disk under externally given gravitational fields (Shu 1974; Zweibel & Kulsrud 1975;...
Supersonic Collisions between Two Gas Streams (1995)
Lee, Hyung Mok, Kang, Hyesung, Ryu, Dongsu
A star around a massive black hole can be disrupted tidally by the gravity of the black hole. Then, its debris may form a precessing stream which may even collide with itself. In order to understand...
The MHD Kelvin-Helmholtz Instability: A Two-Dimensional Numerical Study (1995)
Frank, Adam, Jones, T. W., Ryu, Dongsu, Gaalaas, Joseph B.
Using a new numerical code we have carried out two-dimensional simulations of the nonlinear evolution of unstable sheared magnetohydrodynamic flows. We considered two cases: a strong magnetic field...
Global Aspects of Elliptical Instability in Tidally Distorted Accretion Disks (1995)
Ryu, Dongsu, Goodman, Jeremy, Vishniac, Ethan T.
Tidally distorted accretion disks in binary star systems are subject to a local hydrodynamic instability which excites $m=1$ internal waves. This instability is three dimensional and approximately...
Kang, Hyesung, Ryu, Dongsu, Jones, T. W.
Three-dimensional hydrodynamic simulations of large scale structure in the Universe have shown that accretion shocks form during the gravitational collapse of one-dimensional caustics, and that...
Background X-ray Emission from Hot Gas in CDM and CDM+Lambda Universes: Spectral Signatures (1995)
Cen, Renyue, Kang, Hyesung, Ostriker, Jeremiah P., Ryu, Dongsu
We present a new treatment of two popular models for the growth of structure, examining the X-ray emission from hot gas with allowance for spectral line emission from various atomic species,...
Ryu, Dongsu, Jones, T. W., Frank, Adam
We present for astrophysical use a multi-dimensional numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference method on an Eulerian...
Stable and Unstable Accretion Flows with Angular Momentum near a Point Mass (1995)
Ryu, Dongsu, Brown, Garry L., Ostriker, Jeremiah P., Loeb, Abraham
The properties of axisymmetric accretion flows of cold adiabatic gas with zero total energy in the vicinity of a Newtonian point mass are characterized by a single dimensionless parameter, the...
The Evolution and Efficiency of Oblique MHD Cosmic-Ray Shocks: Two-Fluid Simulations (1994)
Frank, Adam, Jones, T. W., Ryu, Dongsu
Using a new, second-order accurate numerical method we present dynamical simulations of oblique MHD cosmic ray (CR) modified plane shock evolution using the two-fluid model for diffusive particle...
Numerical Magnetohydrodynamics in Astrophysics: Algorithm and Tests for One-Dimensional Flow (1994)
We describe a numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference scheme on an Eulerian grid, called the Total Variation...
Hot Gas in the CDM Scenario: X-Ray Clusters from a High Resolution Numerical Simulation (1994)
Kang, Hyesung, Cen, Renyue, Ostriker, Jeremiah P., Ryu, Dongsu
We exmaine the distribution of hot gas in a standard CDM model of the universe using high resolution hydrodynamic simulations. Adopting standard parameters determined from COBE and light element...
A Comparison of Cosmological Hydrodynamic Codes (1994)
Kang, Hyesung, Ostriker, Jeremiah P., Cen, Renyue, Ryu, Dongsu, Hernquist, Lars, Evrard, August E., ...
We present a detailed comparison of the simulation results of various cosmological hydrodynamic codes. Starting with identical initial conditions based on the Cold Dark Matter scenario for the growth...