Siegfried Glenzer (SIMES Friday Seminar)

Date(s) - Jan 10 2014
11:00 AM - 12:30 PM

Shasta Room, Bldg. 40, Room 361


Exploring the physical properties of matter in extreme conditions

Siegfried H. Glenzer

Distinguished Staff Scientist, SLAC

Abstract: One of the great challenges of this century is to determine if nuclear fusion of hydrogen isotopes can be demonstrated in the laboratory and developed into an unlimited carbon-free energy source.  The worldwide effort has long been divided into the magnetic confinement fusion approach and laser-driven targets that are designed to reach temperatures and densities more extreme than the center of the sun.  The latter approach had been pursued over the last 4 years at the premier laser fusion facility in the United States, the National Ignition Facility.  These experiments have led to the important finding that the demonstration of a fully burning plasma state will require much improved understanding of the microscopic physics of dense plasmas.  In particular, the compressibility and thermal conductivity of dense matter determine the hydrodynamic instability growth that it is presently the limiting factor for the successful demonstration of ignition fusion targets.

To develop a first-principles experimental validation of modeling of compressed matter we have therefore begun developing novel experiments at the recently commissioned Matter in Extreme Conditions instrument.  Here, we use the seeded LCLS beam with x-ray pulses with the highest peak brightness available today.  This capability allows us to measure plasmons in shock-compressed matter.  For example, high-density aluminum has been compressed up to a mass density of 7 g cm-3 with a free electron density of ne = 4.7 x 1023 cm-3 and a temperature of 35,000.  In these conditions, we visualize the density and pressure evolution by resolving correlations up to distances comparable to the atomic size of aluminum.  Our data allow direct determination of pressure for validating theoretical models for the thermodynamics at high pressure.  In this talk, I will show how these data relate back to the design of ignition fusion experiments and will discuss future plans for the study of hot and dense matter.