Are we in a fusion renaissance?

Fusion is a potentially unlimited source of non-carbon emitting energy. It requires the mashing together of small nuclei such as deuterium and tritium to make another nucleus and a lot of leftover energy. The problem is that nuclei do not want to be mashed together and thus to achieve fusion you need something to confine high energy nuclei for a long enough time. Currently, there are only two methods that have successfully demonstrated fusion: 1) gravitational confinement as in the center of a star, and 2) inertial confinement as in a nuclear bomb. In order to get nuclei at high enough energy to overcome the energy barrier for a fusion reaction, electrons can no longer be bound to nuclei to form atoms. A gas of quasi-neutral hot nuclei and electrons is called a plasma and has often been dubbed the fourth state of matter. Hence, the physics of fusion is mostly the physics of plasmas.

My PhD work was in plasma physics and although my thesis ultimately dealt with chaos in nonlinear partial differential equations, my early projects were tangentially related to fusion. At that time there were two approaches to attaining fusion, one was to try to do controlled inertial confinement by using massive lasers to implode a tiny pellet of fuel and the second was to use magnetic confinement in a tokamak reactor. Government sponsored research has been focused almost exclusively on these two approaches for the past forty years. There is a huge laser fusion lab at Livermore and an even bigger global project for magnetic confinement fusion in Cadarache France, called ITER. As of today, neither has proven that they will ever be viable sources of energy although there is evidence of break even where the reactors produce more energy than is put in.

However, these approaches may not ultimately be viable and there really has not been much research funding to pursue alternative strategies. This recent New York Times article reports on a set of privately funded efforts to achieve fusion backed by some big names in technology including Paul Allen, Jeff Bezos and Peter Thiel. Although there is well deserved skepticism for the success of these companies,  (I’m sure my thesis advisor Abe Bers would have had some insightful things to say about them), the time may be ripe for new approaches. In an impressive talk I heard many years ago, roboticist Rodney Brooks remarked that Moore’s Law has allowed robotics to finally be widely available because you could use software to compensate for hardware. Instead of requiring cost prohibitive high precision motors, you could use cheap ones and use software to control them. The hybrid car is only possible because of the software to decide when to use the electric motor and when to use the gas engine. The same idea may also apply to fusion. Fusion is so difficult because plasmas are inherently unstable. Most of the past effort has been geared towards designing physical systems to contain them. However, I can now imagine using software instead.

Finally, government attempts have mostly focused on using a Deuterium-Tritium fusion reaction because it has the highest yield. The problem with this reaction is that it produces a neutron, which then destroys the reactor. However, there are reactions that do not produce neutrons (see here). Abe used to joke that that we could mine the moon for Helium 3 to use in a Deuterium-Helium 3 reactor. So, although we may never have viable fusion on earth, it could be a source of energy on Elon Musk’s moon base, although solar would probably be a lot cheaper.

Proving I’m me

I have an extremely difficult time remembering the answers to my security questions for restoring forgotten passwords. I don’t have an invariant favourite movie, or book, or colour. I have many best friends from childhood and they have various permutations of their names. Did I use their first name, nick name, full name? Even my Mother’s maiden name can be problematic because there are various ways to transliterate Chinese names and I don’t always remember which I used. The city I met my wife is ambiguous. Did I use the specific town per se or the major city the town is next to? Did I include the model of my first car or just the make. Before I can work my way through the various permutations, I’m usually locked out of my account forever.

As much as I appreciate and rely on computers, software, and the internet, objectively they all still suck. My iPhone is perhaps better than the alternative but it sucks. My laptop sucks. Apple makes awful products. Google, Amazon, Uber and the rest are not so great either. I don’t remember all the times Google Maps has steered me wrong. The tech landscape may be saturated but there is definitely room for something better.