Part 2 of 2 Parts (Please read Part 1 first)
     Helion says that its approach is different from other fusion power reactor designs in three important ways. First, it utilizes a pulsed, non-ignition fusion system. The company explains, “This helps us overcome the hardest physics challenges, build highly energy-efficient devices, and allows us to adjust the power output based on need by adjusting the pulse rate.”
     The second major difference is that the Helion system is built to directly recover all unused and new electromagnetic energy efficiently. The company says, “Other fusion systems heat water to create steam to turn a turbine, which loses a lot of energy in the process.”
     The third important difference is that the Helion fusion reactor uses a deuterium and helium-3 fuel mixture. Deuterium-helium-3 fusion results in charged particles that can be directly recaptured as electricity. The company points out that “This helps keep our system small and efficient, allowing us to build faster and at a lower cost. This fuel cycle also reduces neutron emissions, substantially reducing many of the engineering challenges faced by users of deuterium-tritium fusion fuel.”
     Helion has constructed six prototype fusion reactors over the years. Trenta is its most recent prototype. The company claims that it ran nearly every day for two years. Trenta reportedly completed ten thousand high-power pulses and operated under vacuum for sixteen months. The company says, “With Trenta, Helion became the first private organization to reach plasma temperatures of one hundred eighty million degrees Fahrenheit (9 keV).” After successful test campaigns, Helion shut down Trenta in January of 2023.
     Helion is now focused on constructing its seventh fusion reactor prototype, called Polaris. According to Helion, Polaris is designed to demonstrate the production of a small amount electricity. It will have a higher magnetic field strength and an increase repetition rate when compared to Trenta. Helion hopes to begin the operation of Polaris by early 2024.
     Helion also notes several other technical milestones it has achieved. Among these milestones, the company claims that its magnets operate at over ninety percent energy efficiency. In addition, Helion says that its magnets have achieved compression fields over ten Tesla. It has also achieved sustained plasmas with lifetimes greater than one millisecond. The company says that “With every machine we build, we learn more about the capabilities of our science and technology. With rapid iteration and testing, we have been able to learn quickly and apply what we’ve learned to our next machines.”
     Earlier this year, Microsoft signed a power purchase agreement with Helion to buy electricity from Helion’s first commercial fusion power plant. That unit is expected to produce at least fifty megawatts after an initial ramp-up period. It is projected to come online in 2028.
     David Kirtley is the CEO of Helion. He said in a statement announcing the collaboration with Nucor that “A project like this is only made possible by working with a forward-looking company like Nucor, which is committed to decreasing its carbon emissions.”
     Topalian said that “This project marks a tremendous milestone in the potential for the use of nearly limitless clean electricity for industrial manufacturing. By entering this agreement, we are demonstrating our commitment to be the cleanest steel producer in the world, while setting an example for all manufacturing companies.”

     Researchers under the direction Chang Liu of Princeton Plasma Physics Laboratory (PPPL) have discovered a promising approach to mitigating damaging runaway electrons created by plasma disruptions in tokamak fusion reactors. This approach harnesses a unique type of plasma waves that bears the name of astrophysicists Hannes Alfvén, a 1970 Nobel laureate.
     Alfvén waves have long been known to loosen the confinement of high-energy particles in tokamak reactors. This permits some particles to escape and reduces the efficiency of the donut-shaped fusion reactors. However, the new findings by Chang Liu and his team at General Atomics, Columbia University and PPPL have uncovered new techniques to deal with runaway electrons.
    The researchers found that such loosening can diffuse or scatter high-energy electrons before they can turn into avalanches that damage tokamak components. This process was determined to be circular. The runaway electrons create plasma instabilities that give rise to Alfvén waves that keep avalanches from forming.
     Chang Liu is a staff researcher at PPPL and the lead author of a paper that details the results of his work in the journal Physical Review Letters. He said, “The findings establish a distinct link between these modes and the generation of runaway electrons.”

     Researchers have derived a theory for the circularity of these interactions. The results of their experiments align well with runaway electrons in experiments on the DIII-D National Fusion Facility which is a Department of Energy (DoD) tokamak that General Atomics operates for the U.S. DoE Office of Science.
     Felix Parra Diaz is the head of the Theory Department at PPPL. He said, “Chang Liu’s work shows that the runaway electron population size can be controlled by instabilities driven by the runaway electrons themselves. His research is very exciting because it might lead to tokamak designs that naturally mitigate runaway electron damage through inherent plasma instabilities.”
    Plasma disruptions begin with sharp drops in the multi-million-degree temperatures required initiate and sustain fusion reactions. These drops in temperatures are called “thermal quenches”. They release avalanches of runaway electrons similar to earthquake-produced landslides. Liu said, “Controlling plasma disruptions stands as a paramount challenge to the success of tokamaks,”
     Plasmas are the hot, charged states of matter composed of free electrons and atomic nuclei called ions. Fusion reactions combine light elements in the form of plasmas to release vast amounts of energy. Fusion processes power the Sun and stars. Mitigating the risk of plasma disruptions and runaway electrons would provide a significant benefit for tokamak facilities designed to reproduce the fusion process on Earth.
     The new approach could have implications for the advancement of the International Thermonuclear Experimental Reactor (ITER). ITER is the international tokamak project under construction in France to demonstrate the practicality of fusion energy and could mark a key step in the development of commercial fusion power plants.
     Liu said, “Our findings set the stage for creating fresh strategies to mitigate runaway electrons.” Experimental campaigns in which all three research centers aim to further develop the important findings with respect to runaway electrons.

     China has just launched its biggest nuclear fusion research facility as it continues to pursue the construction of an “artificial sun”. A recent report included images of the interior of the completed main building of the facility in east Chain’s Anhui province. The facility is formally known as the Comprehensive Research Facility for Fusion Technology (CRAFT). It has been nicknamed “Kuafu” who was a mythical giant who attempted to capture the sun. According to an ancient Chinese fable, the giant Kuafu tried to chase and captured the sun to end a drought. Even though the giant died of thirst before he could catch the sun, he is seen to be a symbol of bravery.
      The report showed pictures of some of the facility’s experimental components. There are images of a prototype of one of eight huge orange segment-inspired pieces. The segments come together to form a hollow doughnut-shaped vacuum chamber where the fusion experiments will take place. Also shown in the report was a seven hundred seventy-one-ton superconducting magnet used for magnetic confinement fusion. CRAFT is expected to be finished by the end of 2025. Scientists have already started working on projects at the complex.
     Nuclear fusion occurs when two lighter nuclei combine to form a heavier single nucleus. This process releases massive amounts of energy. It powers the sun and all the stars in the sky. As global demand for carbon-free energy grows. Fusion could be a way of “capturing the sun”.
     Fusion is powered by deuterium and tritium. These two hydrogen variants are found in water around the globe. One quart of seawater has enough deuterium to produce fusion energy equal to burning seventy-nine gallons of gasoline.
     Fusion power generation does not emit greenhouse gases. Instead, it releases helium. The radioactive waste produced by the process can be recycled within a century. Fusion does not use uranium or plutonium. There is no risk of a meltdown at a fusion reactor. 
     CRAFT is part of China’s plan to replicate the power generation process in the sun.
     The Experimental Advanced Superconducting Tokamak (EAST) is a superconducting magnetic fusion energy reactor. It utilizes magnetic fields to confine plasma at very high temperatures. This facility is also located in Anhui. It has had multiple breakthroughs in the generation of fusion energy. These breakthroughs are expected to contribute to the development of the International Thermonuclear Experimental Reactor (ITER) in France which is the biggest fusion experimental reactor in the world.
     Hu Jiansheng is the deputy director of the Institute of Plasma Physics at the Chinese Academy of Sciences. He told an interviewer in 2022 that China had already achieved eighty percent of the key technology for fusion power. He estimated that China could have usable energy in thirty to fifty years.
     CRAFT is a critical stepping-stone to working nuclear fusion as it will be used to test key technologies for the Chinese Fusion Engineering Test Reactor (CFETR) which is a proposed tokamak device for large-scale power generation expected to be completed around 2035.

     Nuclear fusion is a potential source of clean electricity that could have a myriad of uses that could help mitigate climate change. Fusion releases huge amounts of energy by combining light elements in the form of plasma. Plasma is the hot, charged state of matter composed of free electrons and atomic nuclei that makes up ninety-nine percent of the visible universe. Laboratories around the world are working on harnessing fusion reactions to create a virtually inexhaustible supply of safe and clean power to generate electricity.
     Stellarators are twisty devices designed to reproduce the fusion energy that powers the sun and stars. They primarily rely on external magnetic fields to confine a plasma. The stellarator was invented by American scientist Lyman Spitzer of Princeton University in 1951. Much of its early development was carried out by his team at what became the Princeton Plasma Physics Laboratory (PPPL). PPPL has been working for over fifty years on developing the theoretical knowledge and advanced engineering to enable fusion to power the U.S. and the world.
     Early in the development of stellarators, technical problems convinced researchers that they were not a viable route to commercial fusion. Research interest shifted to tokamaks instead. However, in time, tokamaks encountered serious technical problems and interest shifted back to stellarators. Stellarators can operate without the risk of damaging disruptions that doughnut-shaped fusion reactors called tokamaks encounter.
     Scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have found a mathematical shortcut that could help harness nuclear fusion for energy production on Earth. The new methodology permits researchers to more easily predict how well a stellarator can retain the heat crucial to fusion reactors.
     The new technique measures how well a stellarator’s magnetic field can hold on to the fastest-moving atomic nuclei in the hot plasma. This is critical to boosting the overall heat and aiding the fusion reactions. The main question is how scientists can find a shape that holds in as much the heat as possible.
     Alexandra LeViness is a graduate student in plasma physics at the PPPL. “This research shows that we can find the best magnetic field shape for confining heat by calculating something easier—how far the fast particles drift away from the curved magnetic field surfaces in the center of the plasma. This behavior is described by a number known as gamma C, which we discovered consistently corresponds with plasma confinement.” LeViness added that the shortcut advances future stellarator research. He went on to say that “because the more fast-moving particles that stay in the center of the plasma, the hotter the fuel and the more efficient the stellarator will be.”
      Elizabeth Paul is an assistant professor of applied physics at Columbia University and a former presidential fellow at Princeton University. She said, “But using techniques like the one LeViness studied, we have been able to find magnetic configurations for stellarators that contain heat as well as tokamaks can. It’s more challenging for stellarators, but LeViness has helped show that it’s possible.

     Nuclear fusion has been researched for decades. Many failed predictions thru the years have suggested that commercial nuclear fusion was only twenty years away. Huge technical challenges have prevented the dream from coming true but in the last few years, billions of dollars have been invested in a dozen companies working furiously on practical nuclear fusion around the globe.
     Microsoft and Helion Energy of Redmond, Washington announced last Wednesday that they had reached an historic agreement that could pave the way for the world’s first commercial nuclear fusion power plant. Helion is working on building the commercial facility in Washington state. The goal is to put the plant into operation by 2028 which is just five years away.
     Nuclear fusion could provide a potentially limitless source of carbon-free power. There are demonstration fusion reactors running or being constructed around the globe. However, none of them, including Helion’s reactors, have been able to produce more energy than they require to operate, let alone produce enough energy to feed into the electrical grid. Some analysts in the energy industry are skeptical that commercial fusion will ever be possible.
     If Helion’s fusion reactor design is successful, even though serious technical hurdles remain, it would have massive benefits in the long term as clean energy’s “Holy Grail” is finally achieved.
     David Kirtley is the co-founder and CEO of Helion. He said, “This is bigger than just Helion. This shows more broadly that fusion is transitioning from science experiments and science projects demonstrating key physics to now building products and building commercial power plants.”
     Helion and Microsoft have signed a power purchase agreement in which Microsoft agrees to purchase electricity from the fusion startup once the facility is generating significant amounts of electricity. Microsoft needs clean electricity to fuel the operations of its more than two hundred energy-hungry data centers around the world. Up to this point, Microsoft has relied primarily on wind and solar power. These sources have serious limitations because the wind does not always blow, and the sun does not always shine.
     Brad Smith is vice chair and president of Microsoft. He issued a statement which read, “Helion’s announcement supports our own long term clean energy goals and will advance the market to establish a new, efficient method for bringing more clean energy to the grid, faster.”
     The fusion energy market includes companies across the globe. Helion, Zap Energy, Avalanche and General Fusion are all headquartered in the Pacific Northwest. All of these companies have raised significant amounts of money from notable venture capitalists. Helion’s investors include OpenAI CEO Sam Altman and Facebook co-founder Dustin Moskovitz. Other startups have support from Bill Gates and Jeff Bezos.
     Scott Hsu is the U.S. Department of Energy senior advisor and lead fusion coordinator. He cheered the technology’s potential for lowering costs and providing secure energy globally. International experts warn that humanity needs to slash carbon pollution in the next quarter-century to avoid the worst climate change scenarios.
     Hsu said, “Fusion energy has incredible potential to empower people all over the world,” Hsu said by email. “If commercial fusion energy becomes available by the end of this decade, it could ease all the various possible pathways to [carbon] net-zero by 2050.”

Part 2 of 2 Parts (Please read Part 1 first)
     The new IAEA report dedicates each chapter to a different fusion reactor design class. Details are provided including name, status, ownership, host country and organization. Also included is a short description of the device’s goals and main features. The report also provides statistics about publication, funding and other parameters that help create a comprehensive picture of the status of global fusion research efforts.
     Tokamaks and stellarators are the most common fusion research devices and the focus of much of the current research. These are toroidal devices that contain huge magnets that control the movement of plasma where fusion occurs. The plasmas in these devices are a gas of charged particles at extreme temperatures. The IAEA report shows that there are currently more than fifty tokamaks and over ten stellarators in operation around the world. The largest tokamak in the world is the International Thermonuclear Experimental Reactor (ITER). Thirty-five nations are involved in the project which is being constructed in France.
    Another approach includes inertial fusion which uses high-power lasers (or other means) to heat and compress tiny spherical capsules containing fuel pellets. In December of last year, the National Ignition Facility (NIF) in the U.S. used this approach to make significant progress in fusion research. About three thousand one hundred and fifty kilojoules of energy were generated from the two thousand kilojoules energy input from its one hundred and ninety two lasers.
     Omar Hurricane is the Chief Scientist for the Inertial Confinement Fusion Program Design Physics Division, Lawrence Livermore National Laboratory, U.S. He said, “This year we find ourselves in a position where we can talk about the milestones of burning plasmas, fusion ignition, and target energy gain greater than unity in the past tense – a situation that is remarkable.”
     The report also provides details about alternative designs that scientists continue to research for producing fusion. For example, when two ion beams generated by particle accelerator collide, fusion takes place at the collision point. While hydrogen isotopes are the most popular fuels for fusion research, isotopes of other elements are also being tested. One approach is to fuse a single proton with a boron-11 nucleus.
      To demonstrate that fusion can effectively produce electricity, there are increasing efforts towards design and construction of demonstration fusion power plants or DEMOs. The report also dedicates a chapter to the twelve DEMO concepts at various stages of development in China, Europe, Japan, Russia, the Republic of Korea, the United Kingdom and the United States. Varying target completion dates span the next three decades. Barbarino said, “We’ve made significant progress in understanding fusion and its science, but there is still much work to do before it can become a practical source of electricity.”
          Billions of dollars are being poured into fusion research by public and private entities. The world is now involved in a fusion race and the race is heating up. Great wealth awaits the companies who are able to harness nuclear fusion for commercial energy production and other uses. Achieving practical nuclear fusion will solve many problems related to energy production.

     Physicists in Germany at the Max Planck Institute for Plasma Physics recently found a way to minimize a major heat-loss problem plaguing a promising kind of nuclear fusion reactors called a “stellarator”.
     Nuclear fusion takes place when the nuclei of two atoms merge into one. This releases a huge amount of energy. It is the process that power the Sun and other stars. If we could harness the power on nuclear fusion on Earth, it would mark a major advance in the battle against climate change.
     Fusion does not produce any carbon emissions unlike burning fossil fuels. It also does not produce long-lasting radioactive waste unlike nuclear fission. Unlike solar and wind power, fusion does not depend on the weather.
     Nuclear fusion can only take place under extreme heat and pressure. Nobel-winning physicist Pierre-Gilles de Gennes once remarked that recreating fusion on Earth would require scientist to put the “sun in a box.” Scientists have designed a variety of nuclear fusion reactors that can create the conditions needed for fusion. However, they require more energy than they produce. Until that changes, fusion will not be a viable source of power.
     A stellarator is a type of nuclear fusion reactor that looks like a huge donut that has been squished and twisted out of shape. A coil of magnets surrounds the stellarator to create magnetic fields that control the flow of plasma inside it. By subjecting this plasma to extreme temperatures and pressure, a stellarator can force atoms within it to undergo fusion. Compared to other fusion reactors, stellarators consume less power and have more design flexibility.
      However, the stellarator design makes it easier for the plasma to lose heat through a process called “neoclassical transport”. Without heat, you cannot have sustained fusion. Neoclassical transport is also called neoclassical diffusion. It is a type of diffusion seen in fusion power reactors that have a toroidal shape like a donut. It is a modification of classical diffusion. This adds in effects that are due to the geometry of the reactor that gives rise to new diffusion effects.
     In classical transport, particles travel in helical paths around the lines of magnetic force. Particles collide and scatter which leads to some of them exiting the magnetic field and cooling the plasma. Neoclassical transport is created by the geometry of the reactor vessel. Because the magnetic fields are not uniform inside the donut, some particles wind up bouncing back and forth in what are called banana orbits. Some of them diffusion out of the magnetic fields, cooling the plasma.
      Now, researches have reduced heat loss in the world’s biggest and most advanced stellarator, called the Wendelstein 7-X, by optimizing its magnetic coil. They were able to heat the interior of their nuclear fusion reactor to almost fifty-four million degrees Fahrenheit. That is more than twice as hot as the core of the sun. Testing confirmed that their design had specifically minimized heat loss due to neoclassical transport.
     Novimir Pablant is a physicist working on the Wendelstein 7-X. He said “It’s really exciting news for fusion that this design has been successful. It clearly shows that this kind of optimization can be done.”