Philipp Grete

I am a postdoctoral research associate in the Department of Physics & Astronomy at Michigan State University .
In general, my research covers (magneto)hydrodynamic processes and their role in (astro)physical systems. Given my background in computer science I often use (i.e. conduct and analyze) simulations.
Currently, I am working on analyzing and characterizing energy transfer in compressible MHD turbulence, understanding driving mechanisms in astrophysical systems, and investigating the role of turbulent magnetic fields in the formation of supermassive black hole seeds.
Contact information
Office BPS 3248
Email grete [at] pa.msu.edu
Phone +1 (517) 884-5622
Address Department of Physics & Astronomy
Michigan State University
Biomedical Physical Sciences
567 Wilson Road, Room 3248
East Lansing, MI 48824


News and upcoming events

Aug 2018 Last month I took part in the Performance Portability with Kokkos training at Oak Ridge National Laboratory.
The four-day training was organized by the Exascale Computing Project and covered the Kokkos programming model and library for writing performance portable code. In other words, code is only written once and can afterwards be compiled for different target architectures, e.g., CPUs or GPUs, automatically taking into account architecture specific properties such as the memory layout and hierarchy. We are currently implementing this approach and will use it for the next project.

In addition, SparPi, the Raspberry Pi supercomputer model, had another appearance this month at Astronomy on Tap.
I presented a talk on What’s so super in supercomputer? Theory & Practice including a live demonstration. After the presentation, people made ample use of the opportunity to get their hands-on model themselves and directly interact with the live simulation.
May 2018 Our latest paper on Systematic Biases in Idealized Turbulence Simulations has been accepted for publication in The Astrophysical Journal Letters, see Grete et al 2018 ApJL 858 L19.
We show how the autocorrelation time of the forcing is intrinsically linked to the amplitude of the driving field, and how this affects the presence of (unphysical) compressive modes even in the subsonic regime.
I also presented the results at
Apr 2018 The MSU's science festival was a great success. We had a lot of interested people of all ages at our booth.
The assembled supercomputer model featured all components of an actual supercomputer, e.g., power supply units, networking/interconnects, compute nodes, and a frontend. On the frontend we are running TinySPH, an interactive hydrodynamics code that allows for both illustrating high performance computing techniques such as dynamic load balancing, and illustrating physics by changing fluid parameters such as viscosity or density.
In addition, we offered multiple virtual reality experiences including one that featured a magnetohydrodynamic turbulence simulation. Visitors were able to dive into a turbulent box and experience the rich and complex fluid structure interacting with highly tangled magnetic fields from within.
Feb 2018 I am very happy that I was accepted to participate in the 2018 Professional Development Program of the Institute for Scientist & Engineer Educators. This inquiry based teaching training covers multiple workshops where the participants collaboratively design an inquiry activity that will eventually be implemented in class later this year. The first workshop is the "Inquiry Institute" from March 25-28, 2018 in Monterey, CA.

In addition, I will attend SnowCluster 2018 - The Physics of Galaxy Clusters from March 18 - 23, 2018 in Salt Lake City where I present a poster talk of our latest results on "Systematic biases in idealized turbulence simuations".
Feb 2018 Parts for a Raspberry Pi based "supercomputer" arrived.
We will use the system for outreach, e.g., to demonstrate high performance computing, and in class for hands-on tutorials. I am currently setting the system up, which consists of 8x Raspberry Pi 3 for a total of 32 cores with 8 GB main memory.
The system will premiere at MSU's science festival.
Visit our booth at the Expo on April 7 for Hands-on Supercomputing and multiple Virtual Reality experiences.
Nov 2017 I presented the latest the results on energy transfer in compressible MHD turbulence
  • on Nov 14 in the Astrophysics Seminar at Notre Dame
  • on Nov 15 in the MIPSE seminar (Michigan Institute for Plasma Science and Engineering) at the University of Michigan
A recording of the MIPSE seminar is available here.
Sep 2017 My PhD thesis on Large eddy simulations of compressible magnetohydrodynamic turbulence was awarded with this year's Doctoral Thesis Award by the German Astronomical Society.
I presented the work at the Annual Meeting of the German Astronomical Society . See official press release [pdf] (in German), and MSU press releases (in English) from the CMSE department and the College of Natural Science .
Sep 2017 Our article on Energy transfer in compressible magnetohydrodynamic turbulence has been accepted for publication. In the paper, we introduce a scale-by-scale energy transfer analysis framework that specifically takes into account energy transfer within and between kinetic and magnetic reservoirs by compressible effects. The paper appears as a featured article in the journal Physics of Plasmas. Moreover, the article is covered by an AIP Scilight.
Sep 2017 We (PI B. W. O'Shea, Co-PIs B. Côté, P. Grete, and D. Silvia) successfully obtained computing time through an XSEDE allocation. I will use the resources to study driving mechanisms in astrophysical systems.
Aug 2017 I took part in the Argonne Training Program on Extreme-Scale Computing. This intensive two-week training is funded by the DOE's Exascale Computing Project and allowed me to gain knowledge and hands-on experience on next-generation hardware, programming models, and algorithms. I can highly recommend this training to everyone involved in high-performance computing.
Jun 2017 I presented first results of our energy transfer study for compressible MHD turbulence and the method itself