Heat and Gas Diffusion in Comet Nuclei (pdf file 5.5 MB) - ISSI

8 1. Introduction – Observational Overview
of various effects that are being modeled. Thus, to gain confidence in the
procedures of the different numerical codes, the first step is to compare results
of simple, one-dimensional codes from five independent groups based
on predetermined orbit and spin parameters, composition, and some other
physical conditions. Comparisons are focused on understanding the differences
in the implementation of the physics and mathematical procedures in
the computer codes.
Here we do not direct our attention to more complex issues and new
ideas such as complicated mixtures, multi-dimensional geometries, mechanically
restricted and unrestricted outgassing (dust mantle evolution), different
states of matter (amorphous vs. crystalline ice, trapped vs. frozen
volatile components), long-period vs. short-period comets, the nucleus –
coma boundary layer, etc. Instead, we concentrate on modeling techniques
to understand the reality of the physical processes occurring in comet nuclei.