Why do we calculate B-fields in "donut-shaped" regions? Here's a picture of the Tokamak at the JET (Joint European Torus) facility, currently the largest nuclear fusion research facility (located in England). JET has produced 16 MW of sustained fusion output (for about a second), but at the time was using 23 MW of heating power, not to mention the "confinement" power, so certainly not yet useful as a commercial power generation source! The ITER facility is the "next generation" research facility - not yet built - it will be in France, and will likely cost well more than $20 billion (!) According to Wikipedia, its first plasma operation is planned for 2020. If it goes as planned, ITER would produce MORE energy then it uses (but it's a research facility, so that excess energy will be in the form of unused heat, it won't be making electricity) The US was committed to roughly 10% of the costs of this facility, but that doesn't mean congress will support ITER funding - it's not at all clear what our future participation will look like.
This week will start with Ampere's law, and then we'll talk about the vector potential - a kind of rough magnetic analogue to voltage.
I welcome your comments on the class and this website.
Send them to steven.pollock at colorado.edu
(Thanks to Prof. Chuck Rogers for many of our home page image ideas!)