Day 4 and 5 of 5: Plasma Crash Course
These past two days have been pretty routine. Thursday and Friday comprised our last days of intensive plasma physics lectures and free food. I'm pretty much used to the heat now too. The leftovers will probably be demolished by Sunday night, then we must fend for ourselves like ?responsible adults?.
I got a chance to talk to some Princeton graduate students these past couple of days. It's really interesting to find out what they're researching and how life is as a poor grad student. One grad student, originally from Arizona State University, compared life here to his ?party school? undergraduate days. He said that the culture here is so much different due to its atmosphere of intelligence. You can always find yourself in an intellectual conversation because everyone here is seeking a learning experience. The best minds in the world come here to study, so you can't help but become a better student in whatever discipline you desire. The analogy I think of is like going to Micheal Jordan's house to learn to play basketball or studying Roman history in Rome: this is the place to learn physics. The motivation one gets here is comparable to nothing else. That being said, I can't wait to dive into my research on Monday.
Here are the summaries of the last 6 lectures of the crash course.
Introduction to ICF ? Dan Clark, Lawrence Livermore National Laboratory
Inertial Confinement Fusion (ICF) is the theory that one can use the inertia of the atom's own mass to force nuclei to overcome the nuclear strong force and fuse. Lasers focused around a capsule of cryogenic fuel blow off the capsule and force the fuel implode on itself. The heat from the implosion can rise to thermonuclear conditions for fusion. Ignition occurs when the Strong Force is overcome, and a burn wave propagates out with hot neutrons needed for energy consumption. The laser energy needed to produce this phenomena is being built at Lawrence Livermore, and spans the length and width of three football fields. The precise instrumentation was explained as well as the engineering obstacles that have still not been overcome.
Waves in Plasma ? Cynthia K. Phillips, PPPL and Princeton University Dept. of Astrophysical Sciences
This advanced subject was very difficult to grasp, especially coming from an expert who explained every facet of this science without taking a breath. An important attribute of plasma is that electromagnetic waves phase speed is faster than that of light. So the EM wave frequency has special properties. She discussed and derived many important equations as well as how radio frequency waves can be used to heat the plasma.
Plasma Diagnostics ? Jill Foley, Nova Photonics, Inc.
Foley discussed the important tools used to gather useful information from the plasma and the physics behind the tool design.
Capsule Physics ? Dan Clark, Lawrence Livermore National Laboratory
In ICF, the fuel needed to fuse is first put inside a capsule. The capsule design is so important, that any flaw in the structure will cause any hopes of fusion to disappear. Most of the talk centered around mathematical models of instabilities. Richtmyer-Meshkov, Kelvin-Helmholtz, and Rayleigh-Taylor instabilities were applied to how the capsule ablates and how one could change the capsule design to counter these effects. He argued a case of putting layers of different materials to ramp up densities as the outer layer material's density begins to fall.
Plasma Astrophysics ? Michael Brown, Swarthmore College
This was, by far, my favorite lecture of the series. Brown showed how Magnetohydrodynamics and other conservation laws work in astrophysical plasmas. He also showed video clips from the Hinode satellite telescope of the sun's flares and examples of magnetic reconnection.
Phase Space Engineering ? Nat Fisch, Princeton University Dept. of Astrophysical Sciences
Fisch presented a way to heat plasma using rf (radio frequency) waves. He explained the apparatus that creates these waves and mathematical strategies to impose the correct frequency inside the plasma. The frequency one needs inside the plasma is reflected outside the plasma, so he must change the frequency on the fly once the wave is inside the plasma. This is a very hot area now in fusion research.
Posted at 09:14PM Jun 14, 2008 by jlbarton in General | Comments[1]