  We provide a detailed description of the Chimera code, a code developed to
model core collapse supernovae in multiple spatial dimensions. The core
collapse supernova explosion mechanism remains the subject of intense research.
Progress to date demonstrates that it involves a complex interplay of neutrino
production, transport, and interaction in the stellar core, three-dimensional
stellar core fluid dynamics and its associated instabilities, nuclear burning,
and the foundational physics of the neutrino-stellar core weak interactions and
the equations of state of all stellar core constituents -particularly, the
nuclear equation of state associated with nucleons, both free and bound in
nuclei. Chimera, by incorporating detailed neutrino transport, realistic
neutrino-matter interactions, three-dimensional hydrodynamics, realistic
nuclear, leptonic, and photonic equations of state, and a nuclear reaction
network, along with other refinements, can be used to study the role of
neutrino radiation, hydrodynamic instabilities, and a variety of input physics
in the explosion mechanism itself. It can also be used to compute observables
such as neutrino signatures, gravitational radiation, and the products of
nucleosynthesis associated with core collapse supernovae. The code contains
modules for neutrino transport, multidimensional compressible hydrodynamics,
nuclear reactions, a variety of neutrino interactions, equations of state, and
modules to provide data for post-processing observables such as the products of
nucleosynthesis, and gravitational radiation. Chimera is an evolving code,
being updated periodically with improved input physics and numerical
refinements. We detail here the current version of the code, from which future
improvements will stem, which can in turn be described as needed in future
publications.
