Characterizing Magnetohydrodynamic Turbulence in the Small Magellanic Cloud (2009)
Burkhart, Blakesley, Stanimirovic, Snezana, Lazarian, Alex, Kowal, Grzegorz
We investigate the nature and spatial variations of turbulence in the Small Magellanic Cloud (SMC) by applying several statistical methods on the neutral hydrogen (HI) column density image of the SMC...
Magnetic reconnection in accretion disk systems: from BHs to YSOs (2009)
Piovezan, Pamela P., Kadowaki, Luis H. S., Kowal, Grzegorz, Lazarian, Alex
The most accepted model for jet production is based on the magneto-centrifugal acceleration out off an accretion disk that surrounds the central source (Blandford & Payne, 1982). This scenario,...
Plasma Physics Processes of the Interstellar Medium (2009)
Spangler, Steven, Haverkorn, Marijke, Intrator, Thomas, Kulsrud, Russell, Lazarian, Alex, Redfield, Seth, ...
We discuss the outstanding issues of the interstellar medium which will depend on the application of knowledge from plasma physics. We particularly advocate attention to recent developments in...
Lazarian, Alex, Clemens, Dan, Adamson, Andy, Axon, David, De Buizer, James, ...
Science opportunities and recommendations concerning optical/infrared polarimetry for the upcoming decade in the field of cosmology. Community-based White Paper to Astro2010 in response to the call...
Plasma Astrophysics Problems in Star and Planet Formation (2009)
Zweibel, Ellen, Goodman, Jeremy, Ji, Hantao, Lazarian, Alex
The major questions relevant to star and planet formation are: What controls the rate, efficiency, spatial clustering, multiplicity, and initial mass function of star formation, now and in the past?...
Earlier studies of grain alignment dealt mostly with interstellar grains that have strong internal relaxation of energy which aligns grain axis of maximum moment of inertia with respect to grain's...
Beresnyak, Andrey, Lazarian, Alex
We performed a series of high-resolution (up to 1024^3) direct numerical simulations of hydro and MHD strong turbulence. We found that for simulations with normal viscosity the slopes for spectra of...
Wave Decay in MHD Turbulence (2008)
Beresnyak, Andrey, Lazarian, Alex
We present a model for nonlinear decay of the weak wave in three-dimensional incompressible magnetohydrodynamic (MHD) turbulence. We show that the decay rate is different for parallel and...
The Turbulent Warm Ionized Medium: Emission Measure Distribution and MHD Simulations (2008)
Hill, Alex S., Benjamin, Robert A., Kowal, Grzegorz, Reynolds, Ronald J., Haffner, L. Matthew, Lazarian, Alex
We present an analysis of the distribution of H-alpha emission measures for the warm ionized medium (WIM) of the Galaxy using data from the Wisconsin H-Alpha Mapper (WHAM) Northern Sky Survey. Our...
Invited Review, to be published in “Recent Research Developments in Astrophysics,” (2008)
Michael Efroimsky, Alex Lazarian, Vladislav Sidorenko
Complex rotation with internal dissipation. Applications to cosmic-dust alignment and to wobbling comets and asteroids.
ULTRA-HIGH-ENERGY COSMIC RAY ACCELERATION BY MAGNETIC RECONNECTION IN NEWBORN PULSARS (2008)
Investigamos la posibilidad de que los rayos cósmicos ultra energéticos (UHECR) observados arriba del límite GZK sean protones acelerados en zonas de reconección localizadas sobre la...
Invited Review, to be published in "Recent Research Developments in Astrophysics," (2007)
Michael Efroimsky, Alex Lazarian, Vladislav Sidorenko
Complex rotation with internal dissipation. Applications to cosmic-dust alignment and to wobbling comets and asteroids.
RevMexAA (Serie de Conferencias), 9, 97-98 (2000) (2007)
Elisabete M. Gouveia, Dal Pino, Alex Lazarian
We investigate the possibility that the ultra-high energy cosmic ray (UHECR) events observed above the GZK limit are mostly protons accelerated in reconnection sites just above the magnetosphere of...
Subsonic Mechanical Alignment of Irregular Grains (2007)
We show that grains can be efficiently aligned by interacting with a subsonic gaseous flow. The alignment arises from grains having irregularities that scatter atoms with different efficiency in the...
Radiative torque alignment: Essential Physical Processes (2007)
We study the physical processes that affect the alignment of grains subject to radiative torques (RATs). To describe the action of RATs, we use the analytical model (AMO) of RATs introduced in Paper...
Radiative torques: Analytical Model and Basic Properties (2007)
We attempt to get a physical insight into grain alignment processes by studying basic properties of radiative torques (RATs). For this purpose we consider a simple toy model of a helical grain that...
Diffusion Processes in Turbulent Magnetic Fields (2007)
We study of the effect of turbulence on diffusion processes within magnetized medium. While we exemplify our treatment with heat transfer processes, our results are quite general and are applicable...
Separation of the Alfv\'{e}n mode from a turbulent velocity field using wavelets (2006)
Kowal, Grzegorz, Lazarian, Alex
We report the first attempt to mode decomposition of the velocity field using wavelet transforms in the application to the magnetized turbulence analysis. We compare results of the separation with...
Ultra-high-energy cosmic ray acceleration by magnetic reconnection in newborn pulsars (2006)
Ultra-high-energy cosmic ray acceleration by magnetic reconnection in newborn pulsars
Cosmic Ray Scattering in Compressible Turbulence (2006)
Lazarian, Alex, Beresnyak, Andrey
We study the scattering of low-energy Cosmic Rays (CRs) in a turbulent, compressive MHD fluid. We show that compressible MHD modes -- fast or slow waves with wave lengths smaller than CR mean free...
Polarization intermittency in MHD and its influence on turbulent cascade (2005)
Beresnyak, Andrey, Lazarian, Alex
Goldreich-Sridhar model of incompressible turbulence provides an elegant approach to describing strong MHD turbulence. It relies on the fact that interacting Alfvenic waves are independent and have...
Damping of MHD turbulence in Solar Flares (2005)
Petrosian, Vahe, Yan, Huirong, Lazarian, Alex
(Abridged) We describe the cascade of plasma waves or turbulence injected, presumably by reconnection, at scales comparable to the size of a solar flare loop to scales comparable to particle...
GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy (2003)
Benjamin, Robert A., Churchwell, E., Babler, Brian L., Bania, T. M., Clemens, Dan P., Cohen, Martin, ...
GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire), a SIRTF Legacy Science Program, will be a fully sampled, confusion-limited infrared survey of the inner two-thirds of the Galactic...
The Radio-FIR correlation: Is MHD Turbulence the Cause? (2003)
Groves, Brent, Cho, Jungyeon, Dopita, Michael, Lazarian, Alex
The radio - far infrared correlation is one of the tightest correlations found in astronomy. Many of the models explaining this correlation rely on the association of of global magnetic field...
Scaling of ISM Turbulence: Implications for HI (2001)
Cho, Jungyeon, Lazarian, Alex, Yan, Huirong
Galactic HI is a gas that is coupled to magnetic field because of its fractional ionization. Many properties of HI are affected by turbulence. Recently, there has been a significant breakthrough on...
Dust Polarization From Starlight Data (2001)
Fosalba, Pablo, Lazarian, Alex, Prunet, Simon, Tauber, Jan A.
We present a statistical analysis of the interstellar medium (ISM) polarization from the largest compilation available of starlight data, which comprises ~ 5500 stars. The measured correlation...
(Abridged) We have recently proposed that the ultra-high energy cosmic rays (UHECRs) observed above the GZK limit could be mostly protons accelerated in reconnection sites just above the...
Simulations of MHD Turbulence in a Strongly Magnetized Medium (2001)
Cho, Jungyeon, Lazarian, Alex, Vishniac, Ethan
We analyze 3D numerical simulations of driven incompressible magnetohydrodynamic (MHD) turbulence in a periodic box threaded by a moderately strong external magnetic field. We sum over nonlinear...
Statistical Properties of Galactic Starlight Polarization (2001)
Fosalba, Pablo, Lazarian, Alex, Prunet, Simon, Tauber, Jan A.
We present a statistical analysis of Galactic interstellar polarization from the largest compilation available of starlight data. The data comprises ~ 9300 stars of which we have selected ~ 5500 for...
Lazarian, Alex, Pogosyan, Dmitri, Vazquez-Semadeni, Enrique, Pichardo, Barbara
In this paper we test the results of a recent analytical study by Lazarian and Pogosyan, on the statistics of emissivity in velocity channel maps, in the case of realistic density and velocity fields...
Ultra-high-energy cosmic ray acceleration by magnetic reconnection in newborn pulsars (2000)
We investigate the possibility that the ultra-high energy cosmic ray (UHECR) events observed above the GZK limit are mostly protons accelerated in reconnection sites just above the magnetosphere of...
1. PERSONNEL During the reporting year the research staff consisted of (1998)
Neta Bahcall, Renyue Cen, Bruce Draine, Edward Fitzpatrick, Jeremy Goodman, J. Richard Gott, ...
This report provides a summary and bibliography for the research activities at the Princeton University Observatory and Department of Astrophysical Sciences during the period July 1, 1997 to June 30,...
Interstellar Filaments and the Statistics of Galactic HI (1996)
Lazarian, Alex, Pogosyan, Dmitri
This paper presents a statistical explanation of filament formation in the galactic atomic hydrogen. Recently developed technique allows to determine the 3D spectrum of random HI density. We claim...
Cross-Section Alignment of Oblate Grains (1996)
Lazarian, Alex, Efroimsky, Michael
This paper provides a quantitative account of a recently introduced mechanism of mechanical alignment of suprathermally rotating grains. These rapidly rotating grains are essentially not susceptible...
Physics and Chemistry of Purcell's Alignment (1995)
Paramagnetic alignment of suprathermally rotating grains is discussed in view of recent progress in understanding subtle processes taking place over grain surface. It is shown that in typical ISM...