The Latest News
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9/26/11:Obama names Gragory Howes as a 2010 PECASE Award Winner
President Obama today named Gregory Howes as one of 94 researchers to receive the Presidential Early Career Award for Scientists and Engineers, the highest honor bestowed by the United States government on science and engineering professionals in the early stages of their independent research careers. Nominated for this award by NASA, Professor Howes was recognized
for outstanding contributions to improve understanding of the dissipation of turbulence and the resulting heating of heliospheric plasmas, and for leadership in education and outreach activities. See the White House press release , the NASA press release, and the University of Iowa press release for more information. -
7/14/11: Physical Review Letters paper published
Our numerical study of the solar wind dissipation range, entitled "Gyrokinetic Simulations of Solar Wind Turbulence from Ion to Electron Scales," has just been published in Physical Review Letters. Using AstroGK to perform simulations of the entire dissipation range from the ion to the electron Larmor radius scales, we found: (1) a spectral index of the magnetic energy spectrum in remarkable agreement with recent observational studies, (2) turbulent fluctuations appear to retain the polarization properties of the linear kinetic Alfven wave mode, and (3) ion collisional heating peaks at high perpendicular wavenumber although ion collisional damping peak at lower perpendicularq wavenumber, providing the first strong evidence for the ion entropy cascade in an electromagnetic turbulence simulation.
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6/1-3/11: Iowa High Performance Computing Summer School 2011
Sixteen University of Iowa undergraduate and graduate students and postdocs took part in the third annual Iowa High Performance Computing (IHPC) Summer School. Funding by the National Science Foundation enabled the addition of three faculty members: Professor Bill Dorland from the University of Matryland, Professor Suely Oliveira from the Department of Computer Science at the University of Iowa, and Professor Christian Ott from the California Institute of Technology. Course materials were expanded to cover parallel programming using MPI, OpenMP, and CUDA for GPU computing, and students enjoyed hands on experience with the Moffett Si-Cortex supercomputer at the Rosen Center for Advanced Computing at Purdue University and the new Helium supercomputer at the University of Iowa.
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Spring 2011: Helium Supercomputer
Research Services of the Information Technology Services has just built the first supercomputer on the University of Iowa campus. This computer, funded through a collaboration of 12 indepedent faculty researchers (including myself) and the University of Iowa, is an important computational research tool for the contributing groups specifically and for the campus as a whole. University of Iowa. Press Citizen.
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2/3/11: National Science Foundation CAREER Award
My proposal to the National Science Foundation's CAREER (Faculty Early Career Award) Program, entitled "CAREER: Turbulent Dissipation and Plasma Heating in the Near-Earth Solar Wind," has been funded through the Division of Atmospheric and Geospace Sciences. This prestigious award provides five years of funding for the main thrust of my research program on kinetic turbulence in the solar wind, including theoretical, numerical, and observational approaches. See the University of Iowa press release for more information.
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9/29/10: Professor Howes in the news
Comments by Professor Gregory Howes appear in an article on Discovery News about the possibilty of harnessing solar wind power to meet the energy needs of all humanity. The online article may be accessed at this link.
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9/20/10: Monthly Notices of the Royal Astronomical Society Letters Paper Accepted
My paper, entitled "A prescription for the turbulent heating of astrophysical plasmas," has been accepted for publication in the Monthly Notices of the Royal Astronomical Society Letters. This paper used my cascade model for turbulence in weakly collisional plasmas to calculate the ratio of ion to electron heating due to the dissipation of Alfvenic turbulence in astrophysical plasmas. An outcome of this work is a sub-grid-scale model for turbulent heating of the plasma species in weakly collisional plasmas.
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9/7/10: AstroGK Journal of Computational Physics Paper Accepted
Our paper, entitled "AstroGK: The Astrophysical Gyrokinetics Code," has been accepted for publication in the Journal of Computational Physics. This paper represents the important algorithm description and validation of the AstroGK code to enable AstroGK to become a major simulation code for the space and astrophysical plasma community.
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9/1/10: NSF Proposal Funded
My proposal to the NSF/DOE Partnership in Basic Plasma Science and Engineering Program , entitled "Basic Laboratory Experiments of Plasma Turbulence: Alfven Wave Collisions," has been funded for the period 9/1/2010 to 8/31/2013. The proposed investigation aims to to improve our understanding of the fundamental building blocks of plasma turbulence by performing laboratory experiments on the Large Plasma Device (LAPD) at UCLA to measure the nonlinear evolution of Alfven wave collisions. Comparison to nonlinear gyrokinetic simulation results using AstroGK plays a key role in the proposed work. This project involves collaboration between plasma theorists and experimentalists and space plasma experimentalists from the University of Iowa and plasma expiermentalists from UCLA.
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7/9/10: Iowa High Performance Computing (IHPC) Summer School in the news
The second-annual Iowa High Performance Computing (IHPC) Summer School, envisioned, organized, and taught by Professor Gregory Howes on May 25-26, 2010, was profiled in an online article by the Information Technology department at Purdue University. The online article may be accessed at this link.
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6/8/10: NSF TeraGrid Award of 7.36M hours
My proposal to the National Science Foundations TeraGrid project has been awarded 7.36M hours for the period 7/1/2010-6/30/2011 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 as the #4 supercomputer 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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5/26/10: Second Annual Iowa High Performance Computing (IHPC) Summer School
The second-annual Iowa High Performance Computing (IHPC) Summer School was taught by Professor Gregory Howes on May 25-26, 2010 in the University Capitol Center. The program was held in a computer laboratory provided by the Information Technology Services of the University of Iowa, enabling hands-on instruction both on local research computing clusters at the University of Iowa and on remote supercomputing facilities. The goal of the IHPC is to provide hands-on, science-driven training of graduate students in the design of parallel algorithms and in the practical skills required for the successful execution of a high performance computing research program. The lectures and exercises covered a wide range of topics, including parallel computing models, design of parallel algorithms, parallelization using the Message Passing Interface (MPI) and OpenMP libraries, parallel debugging tools, profiling and performance evaluations, optimization, scientific validation and benchmarking, and analysis and visualization.
The 2010 IHPC Summer School taught 16 University of Iowa graduate students from 14 different departments across the university: biochemistry, biomedical engineering, chemistry, chemical and biochemical engineering, economics, electrical and computer engineering, geography, hydroscience and engineering, industrial engineering, Institute for Clinical and Translational Science, management sciences, mechanical engineering, physics and astronomy, and statistics and actuarial science. The students really jumped into the hands-on programming assignments, learning to write, debug, and run parallel code on both a local 64-core linux cluster and a 4536-core SiCortex machine at Purdue University. Course evaluations came back very high for this pilot program, with an overall rating of 5.45/6.00; students also gave a 5.90/6.00 on the question of whether they would recommend this course to others. Course materials are posted online. One student provided nearly immediate feedback, happy to report "I have already managed to parallelize a particle advection code (without collisions), within 24 hours of taking your course. The course offered much insight on not just computing, but aided my understanding of utilizing University resources. I hope this is something that will continue to benefit many students in the future."
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4/1/10: Award of 2.15M hours on NASA's Pleiades Supercomputer
In support of my NASA funded proposal "The Dynamics of the Dissipation Range in Solar Wind Turbulence," I have been awarded 2.15M hours on NASA's Pleiades supercomputer by the NASA Advanced Supercomputing Division. Pleiades is currently the #6 supercomputer in the world, an SGI Altix ICE 8200EX/8400EX with 81920 computing cores boasting a peak performance of 0.973 petaflops. The aim of this computaitonal work is to test a newly constructed suite of observational measures aimed at distinguishing the characteristic wave modes underlying the fluctuations in the dissipation range of solar wind turbulence.
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1/15/10: GK-LAPD Physics of Plasmas Paper Accepted
Our paper entitled "Numerical Modeling of LAPD Alfven Wave Experiments using AstroGK," with my graduate student Kevin Nielson as first author, has been accepted for publication in Physics of Plasmas. This paper presents a comparison of linear simulation results using the astrophysical gyrokinetics code, AstroGK, to the measured linear properties of kinetic and inertial Alfven waves in the Large Plasma Device (LAPD) plasma. Results demonstrate that: (1) finite frequency effects due to the ion cyclotron resonance do not prevent satisfactory modeling of the LAPD plasma using gyrokinetic theory; and (2) an advanced collision operator, recently implemented in AstroGK, enables the code to successfully reproduce the collisionally enhanced damping rates of linear waves measured in recent LAPD experiments. These tests justify the use of AstroGK in the modeling of LAPD Alfven wave experiments and suggest that AstroGK will be a valuable tool in modeling the nonlinear evolution of proposed Alfven wave collision experiments.
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11/30/09: 2010 INCITE Supercomputing Award
An allocation of 12M hours for 2010 has been awarded to my proposal to the highly competitive Department of Energy Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program, entitled "Turbulent Heating of Astrophysical Plasmas." The project will eventually be granted 40M hours over the full three year period. This substantial computing allocation has been granted on the #1 supercomputer in the world, Jaguar at the National Center for Computational Sciences at the Oak Ridge National Laboratory. Jaguar is a Cray XT5 system with 224,162 computing cores boasting a peak performance of 2.33 petaflops. The goal of this computational project using AstroGK is 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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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.