GEMR is a global electromagnetic gyrofluid model. Gyrofluid means that the spatial and temporal evolution of the gyro-averaged moments (density, flow, and temperatures) of the distribution function are solved. GEMR models the outer edge of a tokamak with a circular poloidal cross-section. In GEMR, the kinetic gradients evolve freely, as required by the strength of fluctuating dynamics in the plasma edge region. Transport by gradient-driven turbulence leads to a degradation of the gradients which are maintained by feedback controlled source/sink zones at the radial boundaries. Although GEMR is a global model including a time dependent self-consistent equilibrium, it is based on local model equations. GEMR is a "delta-f" code. The code and model system were developed by Bruce Scott in the early 2000s. From 2015 to 2021, Peter Manz used GEMR for fundamental studies. Particular highlights include the work on turbulent spreading and the I-mode. The code is no longer in use. 

Thank you very much, Bruce!

publications

T. Nishizawa, P. Manz et al. ‘Inference of flow shear from reciprocating plasma potential measurements by means of Gaussian process regression’, Phys. Plasmas 32, 032507 (2025)

T. Tork, P. Manz et al. 'Estimation of turbulent transport coefficients by the conditional variance method', Nuclear Fusion 65 016054 (2025)

P. Manz et al. 'Gyrofluid simulation of an I-mode pedestal relaxation event' Phys. Plasmas 28, 102502 (2021)

P. Manz et al. 'Physical mechanism behind and access to the I-mode confinement regime in tokamaks' Nucl. Fusion 60 096011 (2020)

P. Manz et al. 'Magnetic configuration effects on the Reynolds stress in the plasma edge' Physics of Plasmas 25, 072508 (2018)

P Manz et al. 'On the phase velocity in between weak and strong plasma edge turbulence'  Plasma Phys. Control. Fusion 60 085002 (2018)

R. Häcker et al. 'Estimation of the plasma blob occurrence rate' Physics of Plasmas 25, 012315 (2018)

P. Manz et al. 'Origin and turbulence spreading of plasma blobs' Physics of Plasmas 22, 022308 (2015)

P. Manz et al. 'The influence of finite ion temperature on plasma blob dynamics'  Plasma Phys. Control. Fusion 57, 014012 (2015)

B. Nold, P. Manz et al. 'Turbulent transport across shear layers in magnetically confined plasmas' Physics of Plasmas 21, 102304 (2014)