Gregory G. Howes

I am presently an Associate Professor in the Department of Physics and Astronomy at the University of Iowa, specializing in theoretical plasma physics and its application to space and astrophysical systems.

Partly Cloudy with a Slight Chance of X-Rays: Space Weather Explained is my ongoing popular science book project to explain space weather to the general public.

Kinetic plasma turbulence is my primary research interest, with an emphasis on high-performance computational studies of turbulence in space and astrophysical plasmas using the Astrophysical Gyrokinetics code, AstroGK. My broader research program involves the coordinated use of analytical theory, numerical simulations, spacecraft observations, and laboratory experiments to understand the how the kinetic physics of plasma turbulence leads to the energization of particles.

Below is a movie of a gyrokinetic simulation of an Alfven Wave Collision, the fundamental building block of astrophysical plasma turbulence. Full Page View of Alfven Wave Collision Movie
Download Alfven Wave Collision Movie
Feel free to download and use this movie for your own scientific presentations.
Credit: Howes, Verniero, and Klein, University of Iowa, 2016.

Although my primary research direction is performing massively parallel, nonlinear gyrokinetic simulations to understand better astrophysical turbulence, I also work on the development of simplified analytical models to study the turbulent cascade of energy in the kinetic and to examine the thermodynamics of the plasma in the solar wind. In addition to this, I also work with scientists dedicated to designing, building, and operating instruments for satellite measurements of the turbulent plasmas in space, focusing in particular on analysis of satellite data. Finally, I am involved in the use of AstroGK for the design and interpretation of basic laboratory experiments on plasma turbulence conducted at the Large Plasma Device (LAPD) at UCLA.

Plasma Theory and Computation Group

I lead the Plasma Theory and Computation Group at the University of Iowa. In addition to scientific collaborations with other University of Iowa faculty members, including Professors Fred Skiff, Craig Kletzing, and Don Gurnett, I oversee my own postdoctoral researchers and graduate students.

Current Group Members

  • James Schroeder, Postodoctoral Researcher:

    Jim completed his Ph.D. in 2017, entitled Exploring the Alfven-Wave Acceleration of Auroral Electrons in the Laboratory, under Professor Fred Skiff, with Professors Gregory Howes and Craig Kletzing as co-adviosrs. As a postdoc, Jim is now working to make the final definitive measurement of electron acceleration by inertial Alfven waves in the laboratory, which will provide for the first time providing key experimental evidence to answer one of the longest standing questions in space physics, "How is the aurora created?"

  • Jennifer Verniero, Graduate Student:

    Jenny holds an NSF Graduate Research Fellowship to study plasma turbulence in space and astrophysical plasmas. She created the Alfven Wave Collision movie above as part of her thesis research. She has recently submitted two first-author articles to the Journal of Plasma physics detailed the properties of the localized Alfven Wavepacket collision and its implications for turbulence in space plasmas.

  • Andrew McCubbin, Graduate Student:

    Andrew is using the newly developed field-particle correlation technique to determine the kinetic mechanisms that lead to the energization of particles the occurs in current sheets arising in plasma turbulence. He is currently working on a refined diagnostic for field-particle correlations in the AstroGK code, and will be using that diagnostic to explore the energization of particles in magnetic reconnection.

  • Brandon Bergerud, Graduate Student:

    Brandon has just started working with the Howes Plasma Theory and Computation group at the University of Iowa. He is currently learning to use the AstroGK code and will apply the field-particle correlation technique to understand more completely how the energy of plasma turbulence is converted into particle energy.

Past Group Members

  • Tak Chu Li

    Postdoctoral Research Scholar, Dartmouth College

    Tak Chu worked as a Postdoctoral Researcher with Professor Howes studying kinetic plasma turbulence and collisionless damping, focusing on the fundamental differences in nonlinear energy transfer and damping mechanisms between 2D and 3D turbulence simulations. Now Tak Chu is working at Dartmouth College with Professor Yi-Hsin Liu on magnetic reconnection and its relation toplasma turbulence.

  • Sofiane Bourouaine

    Research Scientist, Florida Institute of Technology

    Sofiance worked as a Postdoctoral Researcher with Professor Howes studying the tangling of magnetic field lines in kinetic plasma turbulence using the Astrophysical Gyrokinetics code, AstroGK. Now Sofiane is working at the Florida Institute of Technology with Professor Jean Perez on high-performance simulations of MHD turbulence in the solar corona.

  • Jason TenBarge

    Associate Research Scholar, Princeton University

    Jason worked as a Postdoctoral Researcher with Professor Howes studying kinetic plasma turbulence and collisionless magnetic reconnection using the Astrophysical Gyrokinetics code, AstroGK. Now Jason studies kinetic plasma turbulence and other kinetic mechanisms (such as magnetic reconnection and collisionless shocks) using the continuum Vlasov simulation code Gkeyll, developed at Princeton.

  • Kevin Nielson

    Research Scientist, Georgia Tech Research Institute

    Kevin completed his Ph.D., entitled Analysis and Gyrokinetic Simulation of MHD Alfven Wave Interactions, in 2012 under Professor Gregory Howes. His thesis work solved analytically for the nonlinear evolution of periodic Alfven wave collisions in the weakly nonlinear limit and validated that analytical solution using nonlinear gyrokinetic AstroGK simulations. This work demonstrated the pathway of nonlinear energy transfer in plasma turbulence, establishing Alfven wave collisions as the fundamental building block of plasma turbulence. Now Kevin works as a Research Scientist doing defense-related research at Georgia Tech Research Institute.

  • Kris Klein

    Postdoctoral Research Scholar, University of Michigan
    Assistant Professor, University of Arizona

    Kevin completed his Ph.D., entitled The Kinetic Plasma Physics of Solar Wind Turbulence, in 2013 under Professor Gregory Howes. His thesis involved the generation of synthetic spacecraft data, using linear kinetic plasma properties, to better understand and interpret measurements of turbulence in the solar wind. After completing his Ph.D., Kris worked closely with Professor Howes to develop the novel field-particle correlation technique, a means to use velocity-space information from spacecraft observations or nonlinear kinetic simulations to determine the kinetic mechanisms of particle energization. He is currently working on Parker Solar Probe related science with Professor Justin Kasper's SWEAP science team at the University of Michigan. In Fall 2018, Kris will begin as an Assistant Professor in the Lunar and Planetary Laboratory at the University of Arizona.