XGC0 is a full-f, five-dimensional (three in physical space and two in the velocity space) Hamiltonian guiding center code for plasma ions in a realistic tokamak flux surface and limiter geometry.
A well-known Hamiltonian guiding center equation of motion by Littlejohn, Boozer, White and others  has been used
Collisions between multiple species (ions, impurities, electrons) are evaluated using a linear Monte-Carlo operator  for test-particle and the operator by Hirshman and Sigmar  for the field-particle part of the collision operator. A fully non-linear Fokker-Planck-Landau collision operator is also available .
XGC uses a cylindrical coordinate system to easily include the X-point and separatrix in the simulation domain. In most of the previous conventional guiding center codes, a flux coordinate system was used for a faster tracing of the guiding center motion. However, such a description contains the plasma safety factor q, which diverges on the separatrix surface. Hence, those codes were not able to include the separatrix region in the simulation domain.
As full-f code, XGC0 can include sources and sinks to account for, e.g., heat and torque input. Neutral particle effects can be studied using a simple Monte-Carlo transport code and for more comprehensive investigations by coupling to DEGAS2 . XGC0 is also capable of simulating self-consistent magnetic perturbations using M3D  as Ampère's law solver
The code is designed to utilize a massively parallel processing system. Particles in each processor run indepen- dently from each other. Hence, the code performance is inherently linear (roughly) with respect to the number of processors. At a given time interval, the kinetic information from all the processors is gathered by a single central processor for the velocity-average evaluation of the macroscopic quantities.
 C. S. Chang et al., Physics of Plasmas 11, 2649 (2004)
 R. G. Littlejohn, Physics of Fluids 28, 2015 (1985), A. Boozer, Physics of Fluids 27, 2441 (1984), R. B. White, Physics of Fluids B: Plasma Physics 2, 845 (1990)
 A. Boozer et al., Physics of Fluids 24, 851 (1981)
 S. P. Hirshman et al., Nuclear Fusion 21, 1079 (1981)
 E. S. Yoon et al., Physics of Plasmas 21, 032503 (2014)
 D. P. Stotler et al., Computational Science and Discovery 6, 015006 (2013)
 G. Y. Park et al., 24th IAEA Fusion Energy Conference, TH/P4-28 (2012)