EUTERPE: Difference between revisions

where the $w_p$ are the weights (contribution to the distribution function) associated to each marker.  

The electric potential is represented on a spatial grid, the electric charge being carried by the markers. Two coordinate systems are used in the code: a system of magnetic coordinates (PEST) $(s, \theta,\phi )$ is used for the electrostatic potential and cylindrical coordinates $(r, z,\phi )$ are used for pushing the particles, where $s=\Psi / \Psi_0$ is the normalized toroidal flux. The change between coordinate systems, which is facilitated by the existence of the common coordinate ($\phi$), is done in a continuous way. The equation for the field is discretized using finite elements (B-splines) and the PETSc library is used for solving it. The integration of the motion is done using a fourth order Runge-Kutta scheme.