Particle-in-cell
From Free net encyclopedia
Particle-In-Cell (PIC) is an algorithm to compute (for example) the trajectories of charged particles in an electromagnetic field. The field is computed in a grid of cells, and the force on the particles is interpolated from the fields on the grid. The action of the moving charged particles is taken into account by integrating the convection current caused by the moving charges.
The particle-in-cell algorithm is derived from the Lagrangian and Eulerian formulations of mechanics, but is not subjected to the same limitations. Louis Moresi developed the computer program "Ellipsis" to consider 2-dimensional PIC finite element code. He is currently leading a team to create a 3D parallel code using the same approach called Underworld. The code has been extended to 3-dimensions for use in various modeling applications including plate tectonics.
Models which include interactions of particles only through the average fields are called PM (particle-mesh). Those which include direct binary interactions are PP (particle-particle). Models with both types of interactions are called PP-PM or P3M.
In plasma physics simulation, PIC is used to study kinetic effects which are smoothed out in the fluid approximation. PIC simulation is usually parallelized running on multiple machine with domain or particle decomposition. PIC simulation has been used successfully to study magnetic reconnection, electron acceleration and ion heating in auroral region.Template:Physics-stub