cgs.jhuapl.edu for the actual site)

GAMERA running here in your browser

Grid Agnostic MHD for Extended Research Applications

About

GAMERA is a new magnetohydrodynamic (MHD) simulation tool building and improving upon the high-heritage Lyon-Fedder-Mobarry (LFM) code. GAMERA has been written completely from scratch in modern Fortran and provides a flexible, portable, and exascale-capable MHD code. GAMERA features multiple improvements over LFM including: minimal external library dependence, high degree of optimization, OpenMP parallelism allowing use of heterogeneous architectures, and multiple numerics upgrades. Thus, while preserving all key numerical algorithms underlying the LFM code, GAMERA provides a robust and user-friendly solution for sustainable future.

In CGS, a global magnetosphere configuration of GAMERA will serve as the backbone of the geospace part of the MAGE model, will incorporate the other magnetospheric components and ultimately couple to the WACCM-X model of the atmosphere-ionosphere system.

Contact info: gamera-devel@listserv.jhuapl.edu

This static page demonstrates very early-stage technology, that emulates a Linux environment and lets you run the actual gamera code. However, only using what your browser provides, meaning, the performance is minimal. Also, at this point of development, the writing of HDF5 files is not supported, so you will see a "Killed" message at the point when I/O occurs. It will take about 1 min until the command prompt apprears. Then, you can use the editor `vim` to edit any files, such as the initial conditions files at /app/examples/mhdtests/*.xml. You can also execute the code by typing ./gamera.x /app/examples/mhdtests/loop2d.xml

History

LFM code was rewritten by J. Lyon, J. Fedder and C. Mobarry at NRL in the 1980's. Its heritage is traced back to pioneering work on Flux Corrected Transport (FCT) schemes in the same group (J. Boris, D. Book, S. Zalesak, K. Hain). Initial simulations started with very high order spatial interpolation schemes (e.g., 20th order), which was later reduced to 8th order standard today. Over the years, the LFM code or its derivatives have been applied to the terrestrial magnetosphere, planetary magnetospheres (Saturn, Neptune, Uranus, Venus), to inner and outer heliosphere, and regional magnetotail simulations. In 2000's the code was MPI-parallelized which allowed very high resolution simulations reproducing magnetopause boundary instabilities (Kelvin-Helmholtz) and flux-tranfer events (FTEs), ionospheric field-aligned currents with remarkable resemblence to observations, and dipolarization fronts in the magnetotail. Also in 2000's, as part of the Center for Integrated Space Weather Modeling (CISM), a geospace model coupling framework was developed, which allowed implementation of coupling with the Rice Convection Model (RCM) of the inner magnetosphere and the NCAR TIEGCM model of the ionosphere-thermosphere. Finally, in the late 2000's LFM was extended to include the capability to simulate multiple ion fluids. This extension has become known as Multi-Fluid LFM (MFLFM).

Applications

GAMERA was written in a very flexible way and allows easy adaptation to different geometries and initial/boundary conditions via user files. The primary current applications are the terrestrial magnetosphere, the inner heliosphere/solar wind, magnetospheres of outer planets, current sheets and reconnection, and MHD instabilities (e.g, Kelvin-Helmholtz and Rayleigh-Taylor.)

References

Lyon, J. G., Fedder, J. A., & Mobarry, C. M. (2004). The Lyon-Fedder-Mobarry (LFM) global MHD magnetospheric simulation code. Journal of Atmospheric and Solar-Terrestrial Physics, 66, 1333. http://doi.org/10.1016/j.jastp.2004.03.020

Merkin, V. G., & Lyon, J. G. (2010). Effects of the low-latitude ionospheric boundary condition on the global magnetosphere. Journal of Geophysical Research, 115(A), A10202.