The Donut Trilogy: A Plasma Primer

The Science Behind Fusion Energy News

There is a growing amount of fusion related news lately. I recently began writing a series of articles to provide technical commentary on some of these news items. But plasma physics is such an arcane subject that it is difficult to write about without alienating many potential readers. I decided to write some background material first. I have written three introductory articles about magnetized fusion plasmas that I am calling the "Donut Trilogy"

In these articles I use almost no math. Instead, I try to convey the essential physics with liberal use of analogies, imagery, and humor. Although I adopt a conversational style, I intend no irreverence for the subject matter, or certainty of my mastery of it. It is tricky stuff.

Please leave comments after the articles and/or send direct messages to me with your constructive feedback. I wrote these three articles because of excellent feedback I received after my first piece. Thank you to those that have encouraged this process. I have enjoyed it.

Without further ado, I present:?

The Donut Trilogy

Click on the thumbnail images to open each article.

Part I: Burning Donuts

This first article is a lesson on how deceptively simple magnetized fusion energy can seem. We begin with a story about driving in the snow(?). Next, we describe how to build a magnetic confinement experiment in 5 easy steps. Finally, we use what we learned about ice-driving to explain why early plasma confinement experiments were spectacular failures.

Part II: Donut Wars

This article gives a preview of a possible showdown between two of today’s best candidates for fusion reactors. First, we describe how Tokmaks and Stellarators each solved the plasma confinement problem described in part-I. Then we do a tail-of-the-tape comparison of these two reactor designs, à la boxing commentators before a prize fight.?

Part III: Free Mini-Donuts

In this article we ‘discover’ a footloose cousin to plasmas of part-II. Using only the bare-bones physics from part-I, we find a donut-shaped plasma structure that is capable of self-organization. Spheromaks are the magnetic smoke rings of the plasma world. We then close the Donut Trilogy with a glossary of the 4 different reactor types we have encountered and their pastry counterparts.?

Bonus Material: My Plasma Teacher

This article reflects on the often frustratingly empirical nature of plasma physics. Plasma physics is certainly a science, but it involves far more zoology than any non-plasma physicist could imagine. Those interested in taming the plasma beast would do well to watch the award-winning documentary: My Octopus Teacher.?

Fusion Energy News Ahead

Going forward I will be writing articles addressing fusion energy topics in the popular press. The material found in the Donut Trilogy should provide a useful reference for readers without plasma physics training. I may eventually add to the articles linked above should the need arise. Please ‘follow’ me on LinkedIn if you would like to be notified when any future articles come out. Thank you for reading!