ASTRONOMY COLLOQUIUM<br>High-Energy-Density Astrophysics in the Laboratory

Laboratory astrophysics is the colloquial term for experimental work
performed in the lab motivated by astrophysical questions. In general,
this type of work complements observational and numerical astronomy;
from spectroscopic studies, to astrochemistry, to high energy physics,
and others. It is the high-energy-density (HED) environments, or systems
with pressures >1Mbar, that I am interested in exploring. I will discuss
a number of HED topics currently being pursued by myself and colleagues
at the University of Michigan, as well as fellow scientists and
collaborators at other institutions.

High-power-laser facilities provide an unique opportunity to explore the
HED regime in a controlled and diagnosable manner. Much of the
infrastructure for these facilities is provided by the inertial
confinement fusion (ICF) program being pursued around the world. I will
touch briefly on the basics of ICF and demonstrate how this leads
directly to the use of these facilities for basic plasma nuclear
science. As stellar energy is created in HED plasma, the controlled
study of these nuclear reaction can lead to a better understanding of
the system as a whole.

These laboratory systems can be directly scalable to a specific
astrophysical object when specific similarity conditions hold. I will
discuss the theory behind these criteria and provide a well-scaled
experiment that investigated Rayleigh-Taylor growth in core-collapse
supernovae. Much work goes into developing this kind of platform, where
a well-scaled experiment may be performed with respect to a specific
object of interest. In many cases, however, direct scaling is not
possible. Rather, achievement of specific dimensionless parameters in
the lab is required to reach a relevant physics regime and measurements
of these systems may be used as benchmarks for astrophysical codes. I
will discuss a number of experimental platforms currently under
development to investigate: the formation of collisionless shocks and
the role of self-generated magnetic fields, the dynamics and evolution
of supersonic magnetized jets, and the production of relativistic
electron-positron jets.

Colloquia are generally preceded by tea and cookies at 3:30 in the Owl room (Dennison 845). For more information, please contact astro.colloquia@umich.edu.

Astronomy Colloquia listings for Winter 2014.