SPS and the Department of Physics and Astronomy

Daren Stotler,
Princeton Plasma Physics Laboratory

"Controlled Fusion Energy: Promise and Problems"

Thursday, April 26, 2:00pm
Ward Beecher 2006

  Abstract :   Energy  and energy prices are in the news continually: California brownouts, drilling in wildlife refuges, OPEC tightening its grip,  the connection between climate change and energy use. Estimates of fossil fuel reserves and consumption rates indicate that in a few  generations they will not play a prominent role in our civilization's energy portfolio.

 Fusion, the process by which the sun and all the stars shine, may be a long term solution to civilizations thirst for energy.  The US  and other nations have invested substantial money and resources  in trying to understand the scientific questions raised during the
 quest for fusion energy. We will focus on the recent advances in fusion science and speculate on future developments.


 "How Do You Hold onto a Star?"

Thursday, April 26, at 4:00 pm
Ward Beecher 2006

  Abstract: Operating a fusion reactor is like holding onto a star. The plasma facing components used in magnetic confinement fusion devices see plasmas with temperatures equal to, or in most cases, greater than those of the solar photosphere. The heat fluxes to these surfaces can be comparable to those found two solar radii away from the Sun. Plasma-material interactions at the edge of the plasma have a strong effect on its transport properties, even at the core of the plasma. Consequently, a full understanding of the behavior of fusion plasmas requires sophisticated diagnostics to monitor the conditions of wall materials and complete numerical models that describe those conditions.

Such models are incorporated into a code that computes the transport and subsequent ionization of neutral gas, mostly hydrogen, which emerges from plasma-material interactions and predicts atomic emission profiles measured in the experiment.  Codes of this
type are typically coupled to a plasma transport code that predicts the spatial variation of the plasma temperature and density. These
codes have successfully simulated the experimentally observed "detached" regime in which a cold, recombining plasma exists
near the material surfaces a few centimeters away from the core plasma, which is roughly a thousand times hotter. The resulting
insight into the atomic physics processes that transfer momentum and energy from the ionized plasma to the neutral gas will be valuable in other areas of plasma science.

There will be light refreshment in the conference room before the 4:00pm talk.