New nuclear fusion reactor design may be a breakthrough

Using permanent magnets may help to make nuclear fusion reactors simpler and more affordable.

Visualization of how a stellarator's plasma (orange) can be manipulated using a combination of permanent magnets (red and blue) and superconducting coils (grey rings).

Credit: C. Zhu/PPPL
  • Nuclear fusion is the process of fusing atomic nuclei, which can unleash vast amounts of energy.
  • Nuclear fusion reactors have existed for years, but none of them are able to sustainably produce energy.
  • A new paper describes how permanent magnets can be used on stellarators to control the flow of super-hot plasma.


The promise of nuclear fusion is tantalizing: By utilizing the same atomic process that powers our sun, we may someday be able to generate virtually unlimited amounts of clean energy.

But while fusion reactors have been around since the 1950s, scientists haven't been able to create designs that can produce energy in a sustainable manner. Standing in the way of nuclear fusion are politics, lack of funding, concerns about the power source, and potentially insurmountable technological problems, to name a few roadblocks. Today, the nuclear fusion reactors we have are stuck at the prototype stage.

However, researcher Michael Zarnstorff in New Jersey may have recently made a significant breakthrough while helping his son with a science project. In a new paper, Zarnstorff, a chief scientist at the Max Planck Princeton Research Center for Plasma Physics in New Jersey, and his colleagues describe a simpler design for a stellarator, one of the most promising types of nuclear fusion reactors.

Fusion reactors generate power by smashing together, or fusing, two atomic nuclei to produce one or more heavier nuclei. This process can unleash vast amounts of energy. But achieving fusion is difficult. It requires heating hydrogen plasma to over 100,000,000°C, until the hydrogen nuclei fuse and generate energy. Unsurprisingly, this super-hot plasma is hard to work with, and it can damage and corrode the expensive hardware of the reactor.

Stellarators are devices that use external magnets to control and evenly distribute the hot plasma by "twisting" its flow in specific ways. To do this, stellarators are outfitted with a complex series of electromagnetic coils that create an optimal magnetic field within the device.

"The twisted coils are the most expensive and complicated part of the stellarator and have to be manufactured to very great precision in a very complicated form," physicist Per Helander, head of the Stellarator Theory Division at Max Planck and lead author of the new paper, told Princeton Plasma Physics Laboratory News.

The new design offers a simpler approach by instead using permanent magnets, whose magnetic field is generated by the internal structure of the material itself. As described in an article published by Nature, Zarnstorff realized that neodymium–boron permanent magnets—which behave like refrigerator magnets, only stronger—had become powerful enough to potentially help control the plasma in stellarators.

Credit: American Physical Society / Creative Commons Attribution 4.0 International license

"His team's conceptual design combines simpler, ring-shaped superconducting coils with pancake-shaped magnets attached outside the plasma's vacuum vessel," reads an article published in Nature. "Like refrigerator magnets—which stick on only one side—these would produce their magnetic field mainly inside the vessel."

In theory, using permanent magnets on stellarators would be simpler and more affordable, and it would free up valuable space on the devices. But the researchers did note a few drawbacks, such as "limitations in field strength, nontunability, and the possibility of demagnetization."

In any case, commercial nuclear fusion energy won't be available anytime soon, if at all. But, in addition to the new stellarator design idea, there have been some interesting developments in recent years. One of the most noteworthy examples is the International Thermonuclear Experimental Reactor (ITER).

ITER announced last year that it hopes to complete the construction of the world's largest tokamak nuclear fusion reactor by 2025. The goal of the project is to prove that commercial nuclear fusion is possible by demonstrating that a reactor can produce more energy than it consumes. But even if the ITER experiment is successful, it would likely take until at least 2050 for a nuclear fusion power plant to come online.

Achieving sustainable nuclear fusion energy on Earth remains a "grand scientific challenge" with an uncertain future. What's more, some scientists question whether the energy source really is as clean, affordable and safe as many claim it would be. But new insights into the design of nuclear fusion reactors, like the one described in the new paper, could help to expedite the process of developing what could someday become the primary energy source of a post-carbon society.

Yug, age 7, and Alia, age 10, both entered Let Grow's "Independence Challenge" essay contest.

Photos: Courtesy of Let Grow
Sponsored by Charles Koch Foundation
  • The coronavirus pandemic may have a silver lining: It shows how insanely resourceful kids really are.
  • Let Grow, a non-profit promoting independence as a critical part of childhood, ran an "Independence Challenge" essay contest for kids. Here are a few of the amazing essays that came in.
  • Download Let Grow's free Independence Kit with ideas for kids.
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10 Examples of Settled Science that Are 'Controversial'

Many Americans are being misled on serious scientific issues, and science journalists have to spend an inordinate amount of time debunking myths which seemingly never die.

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Many Americans are being misled on serious scientific issues, and science journalists have to spend an inordinate amount of time debunking myths which seemingly never die.

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The surprise reason sleep-deprivation kills lies in the gut

New research establishes an unexpected connection.

Reactive oxygen species (ROS) accumulate in the gut of sleep-deprived fruit flies, one (left), seven (center) and ten (right) days without sleep.

Image source: Vaccaro et al, 2020/Harvard Medical School
Surprising Science
  • A study provides further confirmation that a prolonged lack of sleep can result in early mortality.
  • Surprisingly, the direct cause seems to be a buildup of Reactive Oxygen Species in the gut produced by sleeplessness.
  • When the buildup is neutralized, a normal lifespan is restored.

We don't have to tell you what it feels like when you don't get enough sleep. A night or two of that can be miserable; long-term sleeplessness is out-and-out debilitating. Though we know from personal experience that we need sleep — our cognitive, metabolic, cardiovascular, and immune functioning depend on it — a lack of it does more than just make you feel like you want to die. It can actually kill you, according to study of rats published in 1989. But why?

A new study answers that question, and in an unexpected way. It appears that the sleeplessness/death connection has nothing to do with the brain or nervous system as many have assumed — it happens in your gut. Equally amazing, the study's authors were able to reverse the ill effects with antioxidants.

The study, from researchers at Harvard Medical School (HMS), is published in the journal Cell.

An unexpected culprit

The new research examines the mechanisms at play in sleep-deprived fruit flies and in mice — long-term sleep-deprivation experiments with humans are considered ethically iffy.

What the scientists found is that death from sleep deprivation is always preceded by a buildup of Reactive Oxygen Species (ROS) in the gut. These are not, as their name implies, living organisms. ROS are reactive molecules that are part of the immune system's response to invading microbes, and recent research suggests they're paradoxically key players in normal cell signal transduction and cell cycling as well. However, having an excess of ROS leads to oxidative stress, which is linked to "macromolecular damage and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging." To prevent this, cellular defenses typically maintain a balance between ROS production and removal.

"We took an unbiased approach and searched throughout the body for indicators of damage from sleep deprivation," says senior study author Dragana Rogulja, admitting, "We were surprised to find it was the gut that plays a key role in causing death." The accumulation occurred in both sleep-deprived fruit flies and mice.

"Even more surprising," Rogulja recalls, "we found that premature death could be prevented. Each morning, we would all gather around to look at the flies, with disbelief to be honest. What we saw is that every time we could neutralize ROS in the gut, we could rescue the flies." Fruit flies given any of 11 antioxidant compounds — including melatonin, lipoic acid and NAD — that neutralize ROS buildups remained active and lived a normal length of time in spite of sleep deprivation. (The researchers note that these antioxidants did not extend the lifespans of non-sleep deprived control subjects.)

fly with thought bubble that says "What? I'm awake!"

Image source: Tomasz Klejdysz/Shutterstock/Big Think

The experiments

The study's tests were managed by co-first authors Alexandra Vaccaro and Yosef Kaplan Dor, both research fellows at HMS.

You may wonder how you compel a fruit fly to sleep, or for that matter, how you keep one awake. The researchers ascertained that fruit flies doze off in response to being shaken, and thus were the control subjects induced to snooze in their individual, warmed tubes. Each subject occupied its own 29 °C (84F) tube.

For their sleepless cohort, fruit flies were genetically manipulated to express a heat-sensitive protein in specific neurons. These neurons are known to suppress sleep, and did so — the fruit flies' activity levels, or lack thereof, were tracked using infrared beams.

Starting at Day 10 of sleep deprivation, fruit flies began dying, with all of them dead by Day 20. Control flies lived up to 40 days.

The scientists sought out markers that would indicate cell damage in their sleepless subjects. They saw no difference in brain tissue and elsewhere between the well-rested and sleep-deprived fruit flies, with the exception of one fruit fly.

However, in the guts of sleep-deprived fruit flies was a massive accumulation of ROS, which peaked around Day 10. Says Vaccaro, "We found that sleep-deprived flies were dying at the same pace, every time, and when we looked at markers of cell damage and death, the one tissue that really stood out was the gut." She adds, "I remember when we did the first experiment, you could immediately tell under the microscope that there was a striking difference. That almost never happens in lab research."

The experiments were repeated with mice who were gently kept awake for five days. Again, ROS built up over time in their small and large intestines but nowhere else.

As noted above, the administering of antioxidants alleviated the effect of the ROS buildup. In addition, flies that were modified to overproduce gut antioxidant enzymes were found to be immune to the damaging effects of sleep deprivation.

The research leaves some important questions unanswered. Says Kaplan Dor, "We still don't know why sleep loss causes ROS accumulation in the gut, and why this is lethal." He hypothesizes, "Sleep deprivation could directly affect the gut, but the trigger may also originate in the brain. Similarly, death could be due to damage in the gut or because high levels of ROS have systemic effects, or some combination of these."

The HMS researchers are now investigating the chemical pathways by which sleep-deprivation triggers the ROS buildup, and the means by which the ROS wreak cell havoc.

"We need to understand the biology of how sleep deprivation damages the body so that we can find ways to prevent this harm," says Rogulja.

Referring to the value of this study to humans, she notes,"So many of us are chronically sleep deprived. Even if we know staying up late every night is bad, we still do it. We believe we've identified a central issue that, when eliminated, allows for survival without sleep, at least in fruit flies."

Withdrawal symptoms from antidepressants can last over a year, new study finds

We must rethink the "chemical imbalance" theory of mental health.

Bottles of antidepressant pills named (L-R) Wellbutrin, Paxil, Fluoxetine and Lexapro are shown March 23, 2004 photographed in Miami, Florida.

Photo Illustration by Joe Raedle/Getty Images
Surprising Science
  • A new review found that withdrawal symptoms from antidepressants and antipsychotics can last for over a year.
  • Side effects from SSRIs, SNRIs, and antipsychotics last longer than benzodiazepines like Valium or Prozac.
  • The global antidepressant market is expected to reach $28.6 billion this year.
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