Sequence of Fusion Physics Articles on a Roll

All of these articles bring Heavy Physics but don't be deterred by the highly-scientific content since the overall perspective is what we want in a look at how Fusion Power is being developed in many ways at once which shows there may well be a production tokamak (i.e. fusion power generator) coming.  It won't be soon but there is no lack of trying.

The first approach may be to scan the titles here to get the perspective and that may be enough.  Read deeper as you will and the really Big Dawgs of Physics can dig into the articles for the detail.

Note:  I am not even close to a Big Dawg of Physics but the idea of fusion power is so compelling it makes it fascinating to get an idea of how it evolves.


How to get a bigger bang.

Recently, however, researchers using the Z Machine at Sandia National Laboratories have demonstrated improved control over and understanding of implosions in a Z-pinch, a particular type of magneto-inertial device that relies on the Lorentz force to compress plasma to fusion-relevant densities and temperatures.  The breakthrough was enabled by unforeseen and entirely unexpected physics.

- Science Daily: Breakthrough in Z-pinch implosion stability opens new path to fusion

Once they included the new physics in the modeling, the researchers were able to reproduce and explain the two-dozen observables from the magnetized liner inertial fusion experiments at the Z Machine.  The implosions were found to efficiently convert liner kinetic energy into the internal energy of the fusion fuel and confirm the system behaved as expected and could scale to higher yields on future facilities.  Since the thermonuclear hot spot produced the expected stagnation pressure and was not dominated by 3D instability, it is now thought to provide the basis for a promising route to achieve higher thermonuclear fusion yields in the laboratory.

- Science Daily

Now that is some seriously sexy science talk.  I have no idea of the content except it juices up the tokamak in a big way.

Obtaining Better Control

In dealing with an entity which gets hotter than the Sun, control becomes a highly-desirable aspect to understand.  The content of how they approached the problem is summarized in the article and below is their result.

"This project involved two years of engineers and physicists working hard to create something new, and it's wonderful to see it working successfully on DIII-D," said Dr. David Pace, a physicist who led the project for the GA Energy Group, "Now we get to focus on the next exciting step, which is demonstrating all the ways these variable voltage beams can improve magnetic fusion in machines across the world."

- Science Daily:  General atomics breakthrough enables greater control of fusion energy

If these scientists keep this going, they will be exciting libidinous feelings in women around the world.  Yes, Dagwood, they do like the smart ones ... but not until after high school.  Console yourself until then with porno and sci fi, all the other nerds do.

Enabling Longer Activity Time

You have to eliminate the solenoid so it can run for long periods, see.

(Ed:  I knew that!)

Sure, me too.

The tokamak is an experimental chamber that holds a gas of energetic charged particles, plasma, for developing energy production from nuclear fusion.  Most large tokamaks create the plasma with solenoids -- large magnetic coils that wind down the center of the vessels and inject the current that starts the plasma and completes the magnetic field that holds the superhot gas in place. But future tokamaks must do without solenoids, which run in short pulses rather than for weeks or months at a time as commercial fusion power plants will have to do.

- Science Daily:  Launching fusion reactions without a central magnet, or solenoid

They have stated their Problem to Solve with this result:

The computationally predicted plasmoids have been confirmed with fast-camera images inside the National Spherical Torus Experiment (NSTX), the major fusion facility at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL); the facility has since been upgraded.  The plasmoids merge to form a large ring carrying up to 400,000 amperes of current, creating a plasma start-up phase inside the tokamak.

- Science Daily

They achieved that which they hoped and they obtained yet more science than that.  For the beefy of physics heart, the article presents the detail.

Some Emphasis on Stability Perhaps

When the temperature generated exceeds the Sun, the idea of it getting out of control makes one peach of a sci fi story but an exceptionally short-lived one, I'm afraid.

Here's some detail on the Problem to Solve.

Plasmas in fusion-energy producing devices are gases heated to millions of degrees that can carry millions of amperes of current.  These superhot plasmas must be kept away from material surfaces of the vacuum vessel that contains them by using strong magnetic fields.  When the gas becomes unstable it can touch the chambers' walls, quickly cooling the plasma and disrupting fusion reactions. Such disruption could potentially harm the walls of future fusion-producing devices.  Drs. Jack Berkery and Steve Sabbagh from Columbia University, who work at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL), have developed a potential way to avoid these instabilities.

- Science Daily: Steering a fusion plasma toward stability

There is no pop quiz at the end of this since the primary purpose is to demonstrate how the physicists are slamming on research into improving the fusion energy process in a variety of ways.  That level of activity shows an intent determination to improve every aspect of fusion power generation.

My understanding of what they're doing is general but sufficient to appreciate the scope of the exercise, particularly in concert with the others in this series.  The aggregate makes it all the more convincing that fusion power will come and that highly-talented researchers are doing incredible things to bring it.

We take this to mean it worked (larfs).

Using these ideas, the scientists developed a "stability map" that allows a plasma to be monitored in real-time -- with 1/1000 of a second resolution -- to determine whether it is stable and how close it is to being unstable.  If you know how fast the plasma is rotating and the collisionality, you can use the stability map to see if the plasma is stable, as shown in the accompanying, for an experiment at the National Spherical Torus Experiment at PPPL.  The red colored areas are unstable, and the blue areas are stable.  As the plasma evolves in time, indicated by the arrows on the map, its collisionality decreases and its rotation increases.  These changes lead the plasma to become unstable, and confinement of the plasma is lost, disrupting the fusion reaction.  Controlling the rotation based on the stability map may allow steering the plasma back to a stable region, thereby avoiding disruption of the fusion reaction.

Stability map of fusion plasma in NSTX. Blue is stable and red is unstable. As the plasma decreases collisionality and increases rotation in time it transitions into an unstable region.

Credit: Princeton Plasma Physics Laboratory

- Science Daily