Numerical heating of electrons in particle-in-cell simulations of fully magnetized plasmas.

The role of spatial resolution of the electron gyroradius in electrostatic particle-in-cell (PIC) simulations is studied. It is demonstrated that resolving the gyroradius is crucial for simulations of strongly magnetized plasmas and that nonresolving it results in substantial anisotropic heating of electrons. The numerical heating can, in some cases, be suppressed by the higher-order weighting to the grid, but it cannot be avoided. Possible mechanisms behind this numerical heating are discussed. The study is carried out with a fully three dimensional electrostatic PIC code with an external magnetic and electric fields.