Our primary collaborations with the labs are related to verification
and validation (V&V).

The Center is actively participating in the V&V working group led by
Jamileh Soudah (DOE HQ) and Dan Meiron (CalTech). T. Plewa is the
Chicago's POC with T. Dupont regularly participating in the V&V
activities.

Initial validation interactions (A. Calder. B. Fryxell) with the labs
have been related to the so-called alpha-group inititative, led by Guy
Dimonte (LLNL), concerned with development and growth of the
Rayleigh-Taylor instability. The results has been recently presented
by Dimonte et al. (2005, Phys. Fluids, 16, 1668) and indicate that
numerical hydrocodes consistently underestimate the rate of
instability growth as observed in experiment. Primary suspect are the
initial conditions that may not be carefully measured experimentally,
but there is no clear consensus among former and current participants
in this work with other factors (mass diffusion) possibly playing an
important role.

The early V&V experience and knowledge has been shared with the
scientific community through review-type publications. Calder et al.
has discussed importance of validation in astrophysics (2002, ApJS,
143, 201) and later in more general context of algorithm development
(2004, CiSE, 5, 22).

The Center's recent validation work (G. Weirs, T. Plewa, T. Dupont,
V. Dwarkadas) has been focused around the shock tube experiment at
LANL, also known as a shock-cylinder interaction study. Chris Tomkins
and Mark Marr-Lyon are lead LANL researchers in this project with
Kathy Prestridge being recently named a leader of this
experiment. This work has resulted in a discovery, through integrated
full-scale numerical experiment, physics processes substantially
modifying evolution of the system. In a result, an appropriate
modification of the experimental diagnostic system has been suggested
and is considered for building. The results has been presented at the
5th HEDLA meeting, AMR Chicago workshop, and the 9th IWPCTM
conference. A refereed journal publication is being prepared.

Our future validation work will be focused on a converging shock-tube
experiment (P. Dimotakis, CalTech) and high-energy density (laser)
experiments.  We are also initating a collaboration with Guy Dimonte
(LANL) and his group to study the Landau-Darrieus instability.  The
Center has recognized the need and secure personel required to support
these new initiatives. Several candidates has been interviewed and
three new postdoctoral associates (A. Haque, N. Hearn, G. Jordan) are
joining the Center to work exclusively in the domain of code
validation.

The Center is also actively participating in several international
collaborations providing a platform for algorithm and software
development with associated physics applications offering ideal
testbed for the FLASH code. The collaborations include a group of
astrophysical hydrodynamicists at the University of Palermo, Italy,
led by Salvator Orlando who studies a distruptive effects of shock
waves, heat conduction and cooling on the evolution of interstellar
clouds. The results of this work has been recently submitted to
Astron. & Astroph. journal.

Erik-Jan Rijkhorst, Univ. Leiden, The Netherlands, has implemented and
successfully tested a new highly efficient and scalable ray-tracing
algorithm for photoionization calculations. The algorithm has been
proposed by T. Plewa with parallel implementation overseen by
A. Dubey. No such tool is currently available to
astrophysicists. Rijkhorst in collaboration with G. Mellema and
V. Icke (both Leiden) and T. Plewa and A. Dubey are applying the new
method to study evaporation of molecular clouds and formation and
evolution of dense molecular globules. Plans are being made to extend
the algorithm towards full radiative transfer. The results of this
work are prepared for publication.

A MURI proposal to study ablation effects using picosecond lasers has
been submitted to the Office of Air Force Office by T. Pollock (PI)
and K. Thornton (Co-I), Dept. of Materials Science & Enginneering,
UMich, and recently accepted. T. Plewa, A. Calder, and A. Khokhlov
will be overseeing potential integration of the IBEAM family of
solvers (D. Swesty) with FLASH.

T. Plewa is participating in the project led by P. Drake (UMich) to
study hydrodynamic instabilities in the high-energy density regime of
relevance to astrophysics on the Omega laser.  Related to this is the
NIF Letter of Interest proposing studying supernova hydrodynamics on
this new facility.