Quoted from: https://ccmc.gsfc.nasa.gov/models/modelinfo.php?model=GUMICS

Model Description
GUMICS is a global solar wind-magnetosphere-ionosphere coupling model. Its solar wind and magnetospheric part is based on solving the ideal MHD equations and its ionosphere part is based on solving the electrostatic current continuity equation. Advanced numerical methods such as automatically refined Cartesian octogrid and temporal subcycling are used to speed up the computation. The computational box is from -224 to +32 Earth radii in GSM X and from -64 to +64 Earth radii in Y and Z.

Model Input
Solar wind density, velocity and temperature as well as interplanetary magnetic field components.

Model Output
Magnetosphere: Primary predicted quantities are plasma density, pressure, velocity and magnetic field vector in space and time. Ionosphere: Height-integrated Pedersen and Hall conductances, ionospheric potential, ionospheric electric field, precipitation power, Joule heating power, field-aligned currents, in space and time.

Limitations and Caveats
MHD describes the large-scale behaviour of the magnetosphere. Quantities such as location and intensity of the bow shock, magnetosphere and tail current sheet come out reliably from the model, whereas quantities depending on non-MHD physics (such as Hall physics) are not reliable (for example, the reconnection rate in the tail). The cross polar cap potential found with GUMICS has been found to be consistent with observations. Among the chief uncertainties are the strength of the Region-2 current system and the behaviour of the inner magnetosphere more generally.

References and relevant publications
P. Janhunen et al, The GUMICS-4 global MHD magnetosphere-ionosphere coupling simulation, J. Atmos. Solar-Terr. Phys., 80, 48-59, 2012.
Palmroth.M, T.I.Pulkkinen, P.Janhunen.P. and C.C.Wu, 2003, Stormtime energy transfer in global MHD simulation, J. Geophys. Res., 108(A1), 1048, doi:101029/2002JA009446, 2003.
Palmroth.M, Janhunen.P, Pulkkinen.T.I, and Peterson.W.K: Cusp and magnetopause locations in global MHD simulation, J.Geophys.Res., 106, 29435-29450, 2001.
Janhunen.P, and M.Palmroth, Some observational phenomena are well reproduced by our global MHD while others are not: Remarks on what, why and how, Adv. Space Res., 28, 1685-1691, 2001.
Janhunen.P, and H.E.J. Koskinen, The closure of Region-1 field-aligned current in MHD simulation, Geophys.Res.Lett., 24, 1419-1422, 1997.
Janhunen.P, GUMICS-3 - a global ionosphere-magnetosphere coupling simulation with high ionospheric resolution, ESA Symposium Proceedings on 'Environmental Modelling for Space-based applications', ESTEC, Noordwijk, NL, 18-20 Sep 1996, ESA SP-392, 1996.

Relevant links
GUMICS Website

GUMICS European Space Weather Portal page

CCMC Contact(s)
Lutz Rastaetter
301-286-1085

Developer Contact(s)
Pekka Janhunen