Picard
is a Galactic cosmic ray propagatio code developed at
Innsbruck University. The purpose of the code is the
numerical solution of the cosmic ray transport equations
with a focus on the observed cosmic ray spectra at Earth and
the gamma-ray emission resulting from the interaction of the
Galactic cosmic rays with the interstellar medium. The features of
Picard
include:
Compatibility to Galdef parameter files
MPI-parallel implementation -- allowing computation on distributed memory computers
Efficient computation of spatially 3D CR distributions
Computation of ensuing gamma-ray emission
Possibility of fully anisotropic spatial diffusion
One of the important destinctions of
Picard
is the numerical scheme for the solution of the cosmic ray
transport equation:
For this transport equation mostly steady state
solutions for a given cosmic ray source distribution
are investigated. The majority of other Galactic
cosmic ray propagation codes, however, use some
time-integration procedure to determine such a steady
state solution. While the implementation of a
time-integrating scheme for the transport equation is
relatively simple, such a scheme is not very efficient
and it becomes necessary to determine whether a
steady-state solution has been found.
Therefore,
Picard
uses an alternative method, where a steady-state
solution is computed directly. While the
implementation of the corresponding scheme is more
difficult than for a time-integration scheme, it turns
to be numerically more efficient than other
schemes. Thus,
Picard
allows for very high resolution, spatially 3D
simulations, by which physical effects can be
investigated that are inaccessible at lower spatial
resolution. As a first study, we investigated the
effects of a cosmic ray source distribution restriced
to the vicinity of the Galactic spiral arms, as is
discussed in the cosmic ray section of this site.
Picard
is a relatively new code that is continuously enhanced
and improved. If you are interested in more details,
see the article Kissmann (2014) or contact me directly
via e-mail.
We continuously offer BSc and MSc theses in the context of the
Picard
code for interested students. Possible theses
include both numerical development of the code and
application to specific cosmic ray propagation
problems.