zz (OLD) Casper Dev
Planetesimal Development Models
Protoplanetary development studies, disk system development, proto-Jupiter studies and planetesimal resonance conditions can all be determined via a modified Box_Tree code. The original Box_Tree code was a hybrid of two computer algorithms, a box code and a tree code and was based on a model developed by Wisdom and Tremaine to study protoplanetary disk dynamics. As such, the code is optimized to allow for the inclusion of external potentials under specificied coordinate systems. This provides a self-consistent model of fractal aggregate dynamics along with a full treatment of rigid body dynamics including rotation. The code also allows for particle and cluster trajectories as well as orientations to be followed explicitly and incorporates a local shearing disk model for planetary rings. The tree code provides a method for rapid calculation of interparticle forces thus allowing them to be included as perturbations to the equations of motion.

The version in use within CASPER has been heavily modified and now allows for the tracking of electrostatic forces between grains, charge rearrangement along fractal aggregates, Debye shielding of grains within dusty plasmas, the inclusion of planetary magnetic fields via spherical harmonic expansions and the inclusion of the gravitational potentials of shepherding moons in ring/disk studies. This provides researchers within the Center extensive modeling capabilities for coagulation calculations including both fractal geometries and dynamic charge allocation along fractal fingers. Additionally, Coulomb crystal models in both 2 and 3 dimensions for bounded (periodic and aperiodic) and unbounded conditions are also being investigated. The code is presently undergoing modifications which will allow investigation into EM energy transfer through dusty plasmas as well as advanced gravitoelectrodynamics studies.

The Box_Tree code, written by Derek Richardson, is available for a number of operating systems including VMS, Sun, and Linux. Additional capabilities using specialized 5th order Runga-Kutta methods are also available.