The Latest News
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10/21/09: Magnetic Helicity ApJL Accepted
Our paper, entitled "On the Interpretation of Magnetic Helicity Signatures in the Dissipation Range of Solar Wind Turbulence," has been accepted for publication in Astrophysical Journal Letters. This paper demonstrates that the observed magnetic helicity signature in the of the solar wind is consistent with a dissipation range consisting of kinetic Alfven waves and does not necessarily imply the importance of ion cyclotron damping.
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10/21/09: Solar Wind Temperature Anisotropy PRL Accepted
Our paper, entitled "Magnetic fluctuation power near proton temperature anisotropy instability thresholds in the solar wind," has been accepted for publication in Physical Review Letters. Using
in situ satellite measurements, this papers shows that magnetic fluctuations in the solar wind are enhanced along the temperature anisotropy thresholds of the mirror, proton oblique firehose, and ion cyclotron instabilities. -
9/1/09: JGR Paper on Ionopause at Mars Accepted
Our paper, entitled "Steep, Transient Density Gradients in the Martian Ionopshere Similar to the Ionopause at Venus," has been accepted for publication in the Journal of Geophysical Research. This paper uses Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) data from the Mars Express spacecraft to explore the nature of the Martian ionopause, the boundary separating the ionosphere of Mars for the shocked interplanetary solar wind.
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8/10/09: ApJ Paper on Imbalanced Turbulence Published
Our paper The Turbulent Heating Rate in Strong MHD Turbulence with Nonzero Cross Helicity has been published in the Astrophysical Journal. This paper discusses the conditions under which different conclusions about the nature of imbalanced turbulence are valid.
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8/3/09: NASA Proposal Funded
My proposal to the NASA Solar and Heliospheric Physics Program , entitled "The Dynamics of the Dissipation Range in Solar Wind Turbulence," has been funded for the period 1/1/2010 to 12/31/2012. The proposed investigation aims to use linear Vlasov-Maxwell kinetic theory to construct a suite of observational measures aimed at distinguishing the characteristic wave modes underlying the turbulence in the dissipation range, and employs nonlinear gyrokinetic simulations as a means of testing these measures.
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6/30/09: Entropy Cascade PRL Published
A key paper by our collaboration on the numerical demonstration of the entropy cascade, entitled Nonlinear phase mixing and phase-space cascade of entropy in gyrokinetic plasma turbulence, has been published in Physical Review Letters. This paper presents a numerical investigation of electrostatic turbulence in weakly collisional, magnetized plasma, which can be interpreted as a cascade of entropy in phase space, proposed as a universal mechanism for dissipation of energy in magnetized plasma turbulence.
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6/4/09: NSF TeraGrid Award of 6,000,000 cpu-hours
My proposal to the National Science Foundations TeraGrid project, entitled "Kinetic Dissipation of Astrophysical Plasma Turbulence," has been awarded 6,000,000 cpu-hours for the period 7/1/2009-6/30/2010 on Kraken at the National Institute for Computational Sciences at the University of Tennessee. Kraken is a Cray XT5 with 99,072 computing cores, boasting a peak performance of 1.03 petaflops which places it in the top five computers in the world. The goal of this project is to employ gyrokinetic theory, an elegant and efficient theoretical framework, in conjunction with today's most advanced supercomputing resources, to investigate the dissipation of turbulence in astrophysical plasmas and determine the resulting plasma heating, a key problem of fundamental importance in space physics and astrophysics.
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3/30/09: MPSFP Proposal Funded
My proposal to the Math & Physical Sciences Funding Program, entitled "Calibrated Numerical Guidance for Basic Plasma Turbulence Experiments," has been funded by the Office of the Vice President for Research at the University of Iowa. Funding will support research on gyrokinetic simulations in support of basic plasma turbulence experiments on the Large Plasma Device (LAPD) at UCLA.
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3/27/09: Nonlin. Processes in Geophys. Accepted
My paper, Limitations of Hall MHD as a model for turbulence in weakly collisional plasmas, has been published in Nonlinear Processes in Geophysics.
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2/11/09: Jason TenBarge has accepted postdoc
Jason TenBarge, who will be graduating from the University of Texas at Austin this summer, has accepted the offer of a postdoctoral research position in computational, space, and astrophysical plasma physics in our group at the University of Iowa. He will arrive in Iowa City in late August 2009.
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10/1/08: Reply Comment in PRL Published
Our Reply to a Comment by Mattaheus, Servidio, and Dmitruk on our Physical Review Letter Kinetic Simulations of Magnetized Turbulence in Astrophysical Plasmas was published today. Here we respond to their criticisms of our numerical work on kinetic turbulence and point out that a fluid model alone, such as Hall MHD, is not sufficient to describe turbulence in a kinetic plasma such as the solar wind.
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8/25/08: Begin of Semester at University of Iowa
The Fall 2008 semester at the University of Iowa has begun. As a new Assistant Professor, I am teaching graduate level Plasma Physics this year, and working on establishing my research program at Iowa, focusing on high-performance computational studies of kinetic plasma turbulence in space and astrophysical plasmas.
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5/23/08: JGR Published!
Our recent submission to Journal of Geophysical Research-Space Physics, A Model of Turbulence in Magnetized Plasmas: Implications for the Dissipation Range in the Solar Wind, appears in the May 23, 2008 issue.
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4/14/08: Faculty Position at University of Iowa
I have accepted a Plasma Theory faculty position in the Department of Physics and Astronomy at the University of Iowa . I am currently gearing up to establish my research program there and will begin teaching their graduate plasma physics courses this coming Fall semsester in August. The University of Iowa is a research university with a top ten plasma physics program and, as the home of James Van Allen, has a long and storied history of ground-breaking space physics research.
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3/11/08: PoP Published Online!
My recent submission to Physics of Plasmas, Inertial range turbulence in kinetic plasmas, has just been published online.
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2/15/08: PRL Published!
Our recent submission to Physical Review Letters, Kinetic Simulations of Magnetized Turbulence in Astrophysical Plasmas, appears in the February 15, 2008 issue.
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2/7/08: PoP Accepted!
My recent submission to Physics of Plasmas, Inertial range turbulence in kinetic plasmas, has been accepted. It will appear in the May Special Issue from the APS Division of Plasma Physics Meeting.
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1/25/08: University of Iowa Shortlist
I have been selected for the shortlist for a tenure-track faculty position in theoretical plasma physics in the Department of Physics and Astronomy at the University of Iowa. My interview dates are March 6-7, 2008.
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1/23/08: University of New Hampshire Shortlist
I have been selected for the shortlist for a tenure-track faculty position in Department of Physics at the University of New hampshire. This position is supported by the newly established Center for Integrated Computation and Analysis of Reconnection and Turbulence (CICART) and will be affiliated with the Integrated Applied Mathematics (IAM) Program to be inaugurated in Fall 2008. My interview dates are February 21-22, 2008.
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1/17/08: INCITE Award of 4,000,000 cpu-hours
Along with my colleague Bill Dorland (U. Maryland), I have been awarded a 4,000,000 cpu-hour supercomputer allocation through the INCITE (Innovative and Novel Computational Impact on Theory and Experiment) competition from the Office of Science in the US Department of Energy. Our project, Fluctuation Spectra and Anomalous Heating in Magnetized Plasma Turbulence, will use Jaguar, a Cray XT3/4 system at the National Center for Computational Sciences at Oak Ridge National Laboratory. Read the 2008 INCITE Award press release from the DOE.
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1/3/08: JGR Accepted!
Our recent submission to Journal of Geophysical Research-Space Physics, A Model of Turbulence in Magnetized Plasmas: Implications for the Dissipation Range in the Solar Wind, has been accepted. Look for it soon!
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12/28/07: PRL Accepted!
Our recent submission to Physical Review Letters, Kinetic Simulations of Magnetized Turbulence in Astrophysical Plasmas, has been accepted. Look for it in the upcoming February 15, 2008 issue.
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9/19/07: AstroGK ported to Franklin
AstroGK has been successfully ported to Franklin, the new 19,320 processor Cray XT4 at NERSC.