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The Oliver E. Buckley Condensed Matter Physics Prize, the best science honor in the United States, for geometric classical material analysis has awarded two Chinese nationals.

For” groundbreaking theoretical and experimental studies on the collective electronic properties of materials that reflect topological aspects of their band structure ,” Tsinghua University’s Xue Qikun, 59, received recognition. ( At the same time, Ashvin Vishwanath, 50, a scientist from Harvard University, received recognition for various contributions to the field. )

The first person from China to get the respect is Xue. He assisted in placing Tsinghua University on the laureate list of the Prize, which was given in honor of American electrical engineer Oliver Ellsworth Buckley( 1887 – 1959 ), who made significant contributions to the field of submarine telephony.

If Stanford University’s Zhang Shoucheng had never inspired Xue in 2008, he would not have entered the field of geometrical classical materials, which is more about magnetism. He is an expert in scanning routing microscopy and spectroscopy as well as surface materials.

Xue recently acknowledged in an interview that he wasn’t a top student at school and had failed postgraduate admissions exams and public exams. However, he claimed that after each loss, his work had been harder. He claimed that he is unquestionably a hard-working scientist who works from 7 am to 11 pm every day. & nbsp,

Zhang, who was born in Shanghai, was compared to a child portent. His ability allowed him to enroll at Fudan University, a prestigious Chinese universities, at the age of 15, two years before his peers, and complete his bachelor’s degree at age 18. Finally he went to Germany to study. He enrolled at Stony Brook University in the New York state school system in 1983 to study under Chinese mathematician Franklin Yang, a 1957 Nobel laureate winner. & nbsp, He was born in the US.

Zhang had previously predicted that he would eventually receive the Nobel laureate. Otherwise, on December 1, 2018, Zhang fell to his death from a glass of his San Francisco house, leaving Xue in the wake of the intellectual world’s rising sun. Zhang’s home has claimed that he committed suicide due to depression, but other balances express suspicion.

Zhang was arrested between flight connections in Canada for alleged violations of American sanctions against Iran, and she spent three years under house arrest. Ironically, Zhang passed away on the day he was supposed to meet Huawei’s Chief Financial Officer Meng Wanzhou.

Three days prior to Zhang’s passing, on November 27, 2018, his research team announced a collaboration with Huawei to build electronics.

Hall-like result

Xue and his team became famous after an experiment in late 2012 in which they observed the “quantum anomalous Hall-like result (QAHE)” when electric currents flow in topological materials. They published their findings in the journal Science in 2013.

Franklin Yang praised Xue’s QAHE trial as a” Nobel laureate – level” accomplishment in 2014. & nbsp,

To understand what the QAHE is, one should know about the Hall-like result, which was discovered in 1879 by American physicist Edwin Hall (1855-1938).

Hall altered the course of an electrical current using an electrical area. The breakthrough was applied to various electronic tools and voltage measurements. & nbsp,

In 1980, German physicist Klaus von Klitzing discovered the quantum Hall-like result, a quantized version of the Hall-like result.

In 1988, British-born physicist Duncan Haldane suggested the concept of the QAHE (adding “anomalous” to the description), which is the quantum Hall-like result created in the absence of an external magnetic field.

One of the two most well-liked areas of study in condensed problem science right now is QAHE. Superconducting elements are the other. & nbsp,

Foreign experts from abroad

Zhang was actually one of the 23 co-authors on Xue’s 2013 paper on the QAHE study. & nbsp,

They came up as a result of two initiatives meant to bring Chinese experts from abroad back to their country.

In 1994, Xue graduated from the Chinese Academy of Sciences’ ( CAS ) Institute of Physics with a doctorate. He later held positions as a visiting associate professor at the Department of Physics at North Carolina State University in the US and as an interact research associate at Tohoku University’s Institute for Materials Research in Japan.

He enrolled in China’s” Hundred Talents Program” in 1999 and later came back to work as a teacher at his alma mater, the Institute of Physics at CAS. In 2005, he joined Tsinghua.

In 2006, Zhang and his Stanford team co-wrote a paper about the “quantum spin Hall-like result (QSHE),” which is expected to be used to make low-power-consumption electronics in the future.

Zhang joined China’s” Thousand Talents Program,” a recently expanded welcome-home action, in 2008 with the goal of fostering ties with Chinese researchers worldwide. He didn’t quit Stanford or renounce his US citizen. He made contact with Tsinghua and Xue’s lab through the program.

According to Chinese internet transactions that provide scant information, he assisted Huawei in 2009 in” resolving some tough questions” regarding 5G systems. Additionally, he advised Tsinghua to conduct checks on three geometric insulators.

Zhang was one of the three Oliver Buckley Prize winners in 2012,” for the QSHE’s philosophical forecast and experimental study, opening the area of geometrical insulators.”

Before deciding to begin concentrating on the QAHE in 2008, Xue and his team had no educational background in geometrical materials, according to the media. In four times, he claimed, his crew had tested more than 1,000 materials before observing the QAHE.

According to Xue,” These accomplishments are a result of the ongoing development of China’s scientific and technological prowess as well as the long-term and deep concentration of fundamental scientific study since the national reform and starting up.” So, recognition should go to every scholar on the group and, more important, to the nation.

Nobel laureate

Chinese state media has been highlighting Xue’s accomplishments ever since the American Physical Society( APS ) announced the 2024 Oliver E. Buckley Prize winners on October 24. Since the prize was first given to a Chinese national in 1953, he has received it.

The majority of winners over the past 70 years have been Americans and Britons, with a few being Chinese, Korean, and Japanese scientists. & nbsp,

In actuality, American-born Chinese scientists like Frank Fang( 1988 ), Shen Zhixun( 2011 ), and Wen Xiaogang( 2017 ) had won the Prize.

Daniel Tsui Chee, born in Henan, was among the three recipients of the award in 1984 for the discovery of the fractional quantized Hall-like result. He had studied in a Hong Kong secondary school before pursuing further studies in Augustana College in the US. He won the Nobel laureate in Physics in 1998.

Zhang’s passing

Some observers said Xue may win the Nobel laureate one day. That remains to be seen. But Zhang definitely will not win the Nobel laureate, which cannot be awarded posthumously.

The 55-year-old scientist passed away mysteriously after the US began its investigation into his company, Danhua Capital, in November 2018. It was charged with aiding Taiwanese businesses in obtaining US technology. Since the scientist’s passing, there has been no common update regarding the United States’ investigation of Zhang’S organization.

His household attributed the illness to despair, claiming Zhang had committed suicide.

There are reports that Zhang had significant financial issues involving his company, but some dubious Foreign critics claim Zhang was at the height of his career and lifestyle and speculate that the US may have played a role in his passing.

China awarded Xue the State & nbsp, Natural Science Award( the first prize ) on January 8, 2019, to recognize his accomplishments in the QAHE experiment without mentioning Zhang’s contributions.

Study: Following Huawei’s device progress, US ban goals ASML

At & nbsp, @ jeffpao3 is Jeff Pao’s Twitter account.

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The world is infatuated with artificial intelligence (AI), and for good reason. AI systems can process vast quantities of data in a seemingly superhuman way.

However, current AI systems rely on computers running complex algorithms based on artificial neural networks. These use huge amounts of energy, and use even more energy if you are trying to work with data that changes in real time.

We are working on a completely new approach to “machine intelligence.” Instead of using artificial neural network software, we have developed a physical neural network in hardware that operates much more efficiently.

Our neural networks, made from silver nanowires, can learn on the fly to recognize handwritten numbers and memorize strings of digits.

Our results are published in a new paper in Nature Communications, conducted with colleagues from the University of Sydney and the University of California, Los Angeles.

A random network of tiny wires

Using nanotechnology, we made networks of silver nanowires about one-thousandth the width of a human hair. These nanowires naturally form a random network, much like the pile of sticks in a game of pick-up sticks.

The nanowires’ network structure looks a lot like the network of neurons in our brains. Our research is part of a field called neuromorphic computing, which aims to emulate the brain-like functionality of neurons and synapses in hardware.

Our nanowire networks display brain-like behaviors in response to electrical signals. External electrical signals cause changes in how electricity is transmitted at the points where nanowires intersect, which is similar to how biological synapses work.

There can be tens of thousands of synapse-like intersections in a typical nanowire network, which means the network can efficiently process and transmit information carried by electrical signals.

Learning and adapting in real-time

In our study, we show that because nanowire networks can respond to signals that change in time, they can be used for online machine learning.

In conventional machine learning, data is fed into the system and processed in batches. In the online learning approach, we can introduce data to the system as a continuous stream in time.

With each new piece of data, the system learns and adapts in real-time. It demonstrates “on the fly” learning, which we humans are good at but current AI systems are not.

The online learning approach enabled by our nanowire network is more efficient than conventional batch-based learning in AI applications.

In batch learning, a significant amount of memory is needed to process large datasets, and the system often needs to go through the same data multiple times to learn. This not only demands high computational resources but also consumes more energy overall.

Our online approach requires less memory as data is processed continuously. Moreover, our network learns from each data sample only once, significantly reducing energy use and making the process highly efficient.

Recognizing and remembering numbers

We tested the nanowire network with a benchmark image recognition task using the MNIST dataset of handwritten digits.

The greyscale pixel values in the images were converted to electrical signals and fed into the network. After each digit sample, the network learned and refined its ability to recognize the patterns, displaying real-time learning.

Using the same learning method, we also tested the nanowire network with a memory task involving patterns of digits, much like the process of remembering a phone number. The network demonstrated an ability to remember previous digits in the pattern.

Overall, these tasks demonstrate the network’s potential for emulating brain-like learning and memory. Our work has so far only scratched the surface of what neuromorphic nanowire networks can do.

Zdenka Kuncic is Professor of Physics, University of Sydney and Ruomin Zhu is a PhD student, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Taiwan has reinforced a critical missile command center against the threat of High-Altitude Electromagnetic Pulse (HEMP) attacks, a response to growing concerns China may use such weaponry to plunge the self-governing island into chaos before or during a potential invasion and deter a possible US intervention.

Last month, Taiwan News reported that the self-governing island’s Ministry of National Defense (MND) confirmed that the Taiwanese Navy has hardened a key missile command center against possible HEMP attacks but denied any new facility has been built for that express purpose.

Taiwan News notes that there are concerns in Taipei that the People’s Liberation Army (PLA) could detonate nuclear weapons at high altitudes to instantly paralyze all electronic equipment and hamper military defense efforts.

The report notes that the Taiwanese Navy has already completed the Gangping Camp in New Taipei City’s Sanzhi District, which can withstand HEMP attacks. The base is affiliated with the Haifeng Brigade, the Taiwanese Navy’s motorized land-based anti-ship missile unit.

The Gangping Camp’s critical component is reportedly the shielding room, which is designed and constructed according to US military nuclear protection standards.

The Taiwan News report says the structure combines outer steel beams and steel columns to block HEMP radiation electromagnetic waves, reducing their force from as high as 50,000 volts per meter to just 5 volts per meter.

It also notes that the shield room has a complete ship monitoring system for the waters surrounding northern Taiwan and a fire control center for shore-based anti-ship missiles.

Taiwan News says that if China were to launch a HEMP attack, the base in Sanzhi would probably still be able to command the launch of Hsiung Feng II and Hsiung Feng III anti-ship missile launchers in northern coastal areas as well as shore-based Harpoon anti-ship missiles.

China has conducted extensive research into developing HEMP weapons, which it views as critical to its military doctrine.

Vincent Pry notes in a June 2020 study for the US EMP Task Force on National and Homeland Security that China has invested heavily in protecting its own military forces and critical infrastructures from HEMP effects.

Pry says that China views a nuclear HEMP attack as part of information or cyber warfare and thus deserves the highest priority as the most likely kind of future warfare. He says that China could use a low-yield nuclear weapon at high altitudes to generate a HEMP attack that would devastate unshielded electronics.

Pry notes that Chinese military writings have several references to launching HEMP attacks against the US, with China aiming to use HEMP weapons offensively while also defending against them. He also says that China’s military doctrine closely associates cyber-attacks with nuclear HEMP attacks as part of combined operation Total Information Warfare.

L J Eads and other writers note in a September 2023 report by the CCP BioThreats Initiative (CCP BTI) that the defense sector is undergoing a significant transformation due to the integration of AI, big data and cloud computing capabilities, emphasizing the role of EMP weapons as a modern countermeasure.

In that direction, Eads and others note that China has made notable strides in EMP weapons technology including high-power pulse sources and military microwave applications.

They mention China’s growing lead in EMP weapons development, noting China’s patent applications in EMP technology have increased significantly since 2006, accounting for 37% of all global applications and a leading 124 patents focused on high-power microwave technology.

In October 2022, Asia Times reported that China is looking into using nuclear weapons to destroy near-earth orbit satellite constellations such as Starlink, with researchers from the Xian-based Northwest Institute of Nuclear Technology claiming to have developed a model evaluating the performance of nuclear anti-satellite weapons at different altitudes and yields.

Their findings show that a 10-megaton warhead could destroy satellites at an atmospheric near-space altitude of 80 kilometers and cause satellite failures and damage. 

Conventional anti-satellite weapons can only target a limited number of satellites, but a controlled nuclear explosion could destroy multiple satellites in one attack. The simulation shows the possibility of using nuclear weapons in a HEMP attack that disables satellites, warships and power grids.

Moreover, in September 2021, Asia Times reported that China had developed a hypersonic missile that could generate an EMP that instantly damages communication and power lines, crippling a populace within seconds.

With a range of 3,000 kilometers, the new missile would stay within the earth’s atmosphere to dodge space-based early warning systems. Once over the target area, a chemical explosion could be triggered that would compress an electrically charged magnet known as a “flux compression generator,” converting the shock energy to short but extremely powerful EMPs.

Engineering scientist Sun Zheng and his co-researchers claim that it can release 95% of the energy in just 10 seconds, suitable for instantaneous discharge to cause EMP damage.

This weapon would cause the effective burnout of critical electronic devices in the target information network within a range of two kilometers. Compared to other non-nuclear EMP bombs, the weapon would have no batteries.

All told, Taiwan has good reason to harden its defenses against a potential Chinese HEMP attack, as the latter has already simulated using such weapons in a potential forcible seizure of the self-governing island without crossing the nuclear weapons threshold.

A declassified 2005 US National Ground Intelligence Report says that China could favor such an asymmetric response against superior US forces in a Taiwan conflict because it would not inflict any damage to living organisms while at the same time disabling Taiwan’s military and dissuading US carrier battlegroups from intervening.

It goes on to say that a Chinese nuclear HEMP attack would minimize military casualties among Taiwanese and US forces, thus potentially reducing the hostility of the Taiwanese people over a forced “reunification” with the mainland while minimizing the risk of US nuclear retaliation.

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Over the past year, Israel has witnessed an extraordinary wave of non-violent protests, involving hundreds of thousands of activists from across society. The extensive demonstrations were triggered by a judicial overhaul announced by the Israeli government in early 2023.

The government passed into law in July 2023 the first planned change of the overhaul – a so-called “reasonableness” bill. This removed the power of the country’s supreme court (and lower courts) to cancel government decisions deemed “extremely unreasonable.”

The proposed judicial overhaul, which was designed to weaken the judicial branch, plunged Israel into one of the most serious internal crises in its history. An unprecedented pro-democracy civil movement mounted an extensive anti-government campaign aimed at stopping the judicial overhaul.

Each week, hundreds of thousands of Israelis demonstrated. These included several groups of reservists serving in the Israel Defense Forces (IDF) – including pilots and combat units – who refused to report to duty unless the government scrapped the judicial overall.

Benjamin Netanyahu, Israel’s longest-serving prime minister, presided over this internal turmoil. Yet rather than seeking a political compromise, his strategy was to sow political and social division.

Netanyahu and his ministers denounced the pro-democracy demonstrators as “traitors”, “anarchists”, and the “privileged elite.” In fact, the protesters came from all walks of life: tech workers, lawyers, teachers, professionals, as well as members of the security services.

The pro-democracy campaigners, in turn, have referred to Netanyahu as the “crime minister.” This aims to highlight that the prime minister’s newfound impetus to weaken Israel’s judiciary arose after he became embroiled in a criminal trial. He faces multiple corruption charges: bribery, fraud and breach of trust, stemming from three separate cases.

Campaigners also repeatedly charged the government with violating the social contract with its citizens. They accuse the ultra-orthodox bloc, which Netanyahu relies on to hold on to power as part of his coalition, of using the judicial overhaul to preserve its economic interests and political influence and of permanently exempting ultra-orthodox males from serving in the IDF.

Social resilience and political strains

The murderous attacks launched by Hamas on October 7, which triggered the Israel-Hamas 2023 war, have had a unifying effect on Israeli society. The social divisions that marked the confrontations over the judicial overhaul have given way to a rare moment of social unity and rallying around the flag.

One of the key organizations opposing Netanyahu’s judicial overhaul, Brothers in Arms, has now turned its entire logistical, financial and human effort to support the war effort. It is also helping the communities that were devastated after more than 1,300 Israelis were murdered by Hamas terrorists and more than 230 kidnapped.

Meanwhile, several religious Jews volunteered with the ultra-orthodox Zaka organization, which retrieves bodies and body parts after terror attacks. They have been tasked with the terrible duty of identifying victims.

But while Israeli society has pulled together, the country’s leadership has not risen to the occasion. Given the monumental military and intelligence failure Israel experienced on October 7, the Netanyahu government entered the war with a severe legitimacy deficit.

And yet it took the prime minister five days to form an emergency government. This brought in Benny Ganz, former defense minister and the leader of the National Unity party.

Gantz will serve alongside Netanyahu and Defense Minister Yoav Gallant in the “war management cabinet.” Former chief of staff with the IDF, Gadi Eisenkot (National Unity Party), and Ron Dermer, Israel’s minister for strategic affairs – and a close Netanyahu ally – will sit as observers.

The formation of the emergency government does not amount to a National Unity Government, which many Israelis had hoped for. Yair Lapid, the leader of the main opposition party, Yesh Atid, has so far opted not to join the government.

He has justified his decision on two grounds: Netanyahu’s insistence on keeping the extreme right parties in the government and the proposal to form a double security cabinet without establishing clear lines of authority.

Netanyahu’s day of reckoning?

Whereas the ongoing political divide is significant, the more serious tension seems to be between Netanyahu and the security-military establishment.

Since the October 7 attacks, heads of Israel’s key security organizations – the IDF and the intelligence service Shin Bet – have acknowledged their responsibility for the multilayered system failure that enabled the Hamas offensive.

In fact, Netanyahu has refused to assume any responsibility. Worse still, as the Israeli ground invasion into Gaza deepened, Netanyahu wrote on Twitter (now renamed X) at 0100 on October 29:

In contradiction to the lying claims: Under no circumstances and at no stage was Prime Minister Netanyahu warned about Hamas intending to go to war … Every defence official, including the heads of military intelligence and the Shin Bet [Israel’s security agency], believed Hamas was deterred and sought accommodation. This was the assessment that was presented time and time again to the prime minister and the cabinet by all defence officials and the intelligence community up to the outbreak of the war.

The prime minister later deleted the message and apologized. But crucially, he did not say that what he tweeted was wrong. This leaves the strong impression that Netanyahu is still highly invested in passing the blame for Hamas’s attacks to secure his political and personal future. The fear is that this may affect his decisions in relation to the war.

This concern has prompted calls from business leaders, columnists, diplomats and former security personnel, to remove Netanyahu and replace the government, possibly through a constructive vote of no-confidence. Netanyahu is hanging on, for now, but his day of reckoning will come, possibly even before the Israel-Hamas 2023 war is over.

Amnon Aran is Professor of International Relations, City, University of London

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Amid fears of yet another long war in the region, Israel has now begun its ground campaign in Gaza.

The Israel Defence Forces (IDF) has already claimed several successes in its three-week campaign, including the elimination of several terrorist leaders including Ibrahim Biari, who it described as a “ringleader” of the October 7 attacks, and liberating at least one hostage held by Hamas.

But Israel’s military commanders will know that this is unlikely to be a simple operation. Among the factors complicating their mission of eliminating Hamas is the “Gaza Metro”, a vast network of interconnected tunnels within the region. Having invested heavily in subterranean infrastructure over the years, Hamas is counting on this network to aid its survival in the coming weeks.

Underground engineering has a long history in warfare. From antiquity to Vietnam, a range of groups have used tunnels to gain an advantage.

Not only can they provide concealment and freedom of movement, but they also present a range of challenges for the attacking force – they can be hardened against any attacks from the surface. Storming underground networks can also be prohibitively difficult for an attacker, given the limited space available.

Sometimes they work. Sometimes they don’t. For instance, the threat posed by Western airpower caused Islamic State (IS) to construct a large network of tunnels. These tunnels made surveillance and airstrikes difficult and were riddled with traps, making capture by ground forces dangerous and difficult.

These benefits only really work if the tunnels are defended, of course, which wasn’t always the case. For instance, in the 2015 battle for Sinjar, the majority of IS fighters were long gone by the time Kurdish land forces arrived to liberate the city.

Established network

Hamas’s tunnel network presents a unique problem for the IDF. There have been tunnel networks in Gaza for years. Initially used for smuggling, they were quickly turned towards offensive uses, playing a role in kidnapping and weapons storage.

The Hamas subterranean networks really began to evolve after 2012, when restrictions were lifted on the importing of building materials to the region. The militant group was able to redirect construction supplies away from civilian infrastructure projects to expand its underground presence.

While the tunnels vary in quality, many are well-equipped and hardened, and deep enough to evade detection by ground-penetrating radar.

Unsurprisingly, key Hamas allies, including Iran are boasting about the Gaza Metro. The network provides the group with a haven and a means to move around the region unobserved.

It places leadership and organizational infrastructure out of reach from air attacks. The system is laden with supplies as well as weapons and fuel.

Defended, booby-trapped and likely to be populated with human shields and hostages as well as fighters, they will be challenging for even a well-equipped and capable attacking force.

Yet, if not addressed, Hamas may continue to operate irrespective of what happens on the surface. Indeed, as many of the tunnels lead across the border, there is a risk of further incursions, rocket strikes and attacks on IDF forces. And, given the heavily urbanized nature of Gaza, much of the network is beneath civilian infrastructure, which further complicates Israeli operations.

Hamas is a proficient and prolific user of tunnels. But in honing its expertise, the group has also provided Israeli forces with a decades-long crash course in how to deal with their underground operations.

In addition to their own experience with Hamas tunnels, the IDF can also draw upon lessons from the war on terror, where coalition forces had to contend with both natural and purpose-built tunnels, and even US experiences with drug cartels burrowing on their southern border with Mexico.

Bitter experience

While Hamas is counting on its tunnels to cause problems, Israel already has a range of solutions. It has already gained valuable experience in underground operations, having learned hard lessons from the past. A range of innovative purpose-built technologies and strategies can be used to provide the IDF with a technological edge.

Some are simple, such as flooding tunnels with sewage, whereas others are more complex, involving specialized engineering. Some solutions, such as ground-penetrating explosives, might be difficult to use, given the presence of civilians.

Israel has known about the tunnels for a long time and is taking them seriously. Recent operations suggest that the time spent training for this exact scenario is going to pay off, at least to a certain extent.

But dealing with a network of more than 300 miles is still going to represent a massive challenge, and storming or blocking off every part of the system is probably impossible.

Bitter experience has taught Israel most of Hamas’s tactics already – but this does not mean that the group doesn’t have more tricks up its sleeve. Hamas’s recent offensive success was rooted in the way it used a number of relatively low-level capabilities in concert.

For instance, paragliders, ground assaults and rockets only have a limited impact when used individually, but together, were used to devastating effect on October 7.

Now Hamas will be hoping for the same degree of success when acting on the defensive. Depending on how Israel chooses to deal with the issue, they may find their ground forces bogged down in slow-moving subterranean activity, or risk heavy civilian casualties if they simply choose to bomb or collapse the tunnels.

Almost any solution Israel chooses can be turned into a Hamas advantage: both in military and political terms.

Ultimately, Israel has no perfect solution to the complex problem posed by the Hamas underground network. But years of dealing with the Hamas Metro means the IDF is not entirely unequipped to confront the challenge.

It seems inevitable that the next days and weeks will be a bitter and bloody struggle, both in the streets of Gaza and as deep as 70 meters below ground.

Christopher Morris, Teaching Fellow, School of Strategy, Marketing and Innovation, University of Portsmouth

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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This is the second installment in Asia Times Science Editor Jonathan Tennenbaum’s series “Fusion Diary.” For an introduction to the series, readers are encouraged to start with “US abandoning its leadership in fusion energy,” by Matthew Moynihan and Alfred B Bortz. Then read part 1 of the series here. – eds

I am standing in the gallery of the control room of the Joint European Torus (JET) – the world’s largest tokamak reactor, situated in the Culham, England. Built as a cooperative project of European nations, JET has been operating for over 40 years, serving as a workhorse for international cooperation in plasma and fusion research.

In December 2021, JET achieved the latest world record for the amount of energy generated by fusion reactions under controlled conditions. During a 5 second pulse, JET produced 59 MJ of thermal energy from fusion of deuterium and tritium. Taking account of the amount of energy absorbed in heating the plasma to its 100 million degree temperature, JET came within a factor of 3 of reaching so-called scientific breakeven.

As I mentioned in the previous article there is now no reasonable doubt concerning the feasibility of generating large net energy outputs by fusion reactors of the tokamak type. A large portion of the credit goes to experiments on JET, which have produced a wealth of knowledge and experience in the course of four decades of operation.  

The JET launch countdown

I always wanted to see how a large tokamak fusion reactor is operated. With me on the gallery was JET Senior Exploitation Manager Fernanda Rimini, PhD (physics). She explained what was happening in the control room and kindly responded to my flood of questions.

JET operates in pulses (“shots”) up to about 10 seconds long. Each shot constitutes a separate experiment, and the operators generally change the parameters between shots. Typically one shot is run about every 30-40 minutes, to allow time not only to permit the reactor coils and other systems to cool down but also to analyze the data needed to make decisions about the next experiment. Sometimes the scientists ask for more time for thinking and discussion.

Each shot is preceded by a “countdown,” analogous to launching a rocket. JET is an extremely complex machine, particularly when we take account of the numerous auxiliary systems and diagnostic instruments attached to it. Not surprisingly, JET’s control room somewhat resembles the control center of a space mission.

Rimini pointed to a horseshoe-shaped central table, from which the machine is run by operators including a specialist in charge of the magnetic field coils that confine the plasma, another in charge of the vacuum systems, another in charge of the heating systems and so on. An engineer in charge oversees the whole process.

Around the desk are workstations for staff controlling diagnostic systems and monitoring the data output. Finally, a few scientists evaluate the results and make decisions about the next experiment.

Once a shot has been initiated, events inside the reactor unfold too rapidly for the human operators to intervene. Accordingly, the machine has real-time control systems that are programmed in advance. These systems steer the plasma by adjusting the currents in the magnetic coils, changing the parameters of the external heating systems and injecting tiny amounts of substances into the plasma.  

Rimini told me that the countdown to a shot lasts two minutes. First, you start all the subsystems and synchronize them. At the “zero” point of the countdown, the magnetic field coils are activated. It takes about 40 seconds for the coils to reach their full parameters. At that point gas is injected into the toroidal vacuum chamber.

What happens then? The current in the central solenoid is ramped down, and the change in magnetic field strength induces a powerful electric field inside the toroidal chamber, ripping the atoms apart into electrons and nuclei, transforming the gas into a plasma, and inducing an electric current of about 4 million amperes in the plasma. This current heats the plasma to ultra-high temperatures (so-called ohmic heating), while generating a powerful internal magnetic field.

The toroidal coils around the vacuum vessel create an additional magnetic field which, combined with the field generated by the central current, serves to confine the plasma and keep it away from walls of the reactor. The particles circulate in complicated helical trajectories. Poloidal coils, parallel to the torus, help to position the plasma inside the chamber. The auxiliary systems that use particle beams and electromagnetic waves to heat the plasma are turned on.

Controlling this whole process is a remarkable feat. Millions of amperes of current flow through the magnetic coils. During the experiment, the power consumption of the system reaches a peak of 1000 megawatts. Over half of the power comes from onsite generators that convert rotational energy, stored in the motion of two 750-ton flywheels, into a brief pulse of electric power.

Back in the control rooms, screens on the wall show measurements of the main plasma parameters. How dense is the plasma? How hot is the plasma? What is the current in the coils? How much power are we putting in from the heating systems? On the right side of the wall is a screen showing the evolution of the plasma itself, taken by fast video cameras. I was visiting just after a shot was completed and could see view a replay of the shot in slow motion.

Note, that the visible light is only a part of the electromagnetic radiation emitted by the plasma; the core region of the plasma can barely be seen here.

Breakthroughs in computer modeling

I wanted to know how well scientists have learned to control the hot plasma in JET and other tokamak reactors. Plasmas are extraordinarily complex physical systems displaying highly nonlinear behavior and a wide variety of instabilities, which can undermine the functioning of the reactor and even cause serious damage.

In the past, the shortcomings of existing mathematical models and limited computer power made it virtually impossible to simulate and predict the behavior of plasmas in tokamaks and other magnetic confinement fusion devices in a reliable fashion. Tokamak scientists learned, by decades of hard experience, how to avoid certain dangerous areas of instability.

The situation has improved radically. Superfast computers, machine learning and qualitative advances in methods of mathematical modeling of plasma processes now produce a degree of agreement between simulation and experiment that would have been unimaginable in the past.

Not least of all, the new computer codes provide the basis for real-time control of plasmas, steering them away from “bad behavior” and permitting maintenance of a desired steady state.

“There are no huge surprises,” Rimini said. “The models that we have represent the core plasma quite well.” Still, she said, “We need to understand more about what is happening at the edge of the plasma. Not because we don’t really know what happens, but because we are trying to [avoid] large perturbations and have nice little ones instead. And that’s where we are still very much in the research phase.”

The plasma ‘miracle‘

In fact, processes taking place at the “edge” of the plasma have decisive importance for the performance of tokamak reactors. How does it come about that a plasma in JET has an “edge”? One would naturally expect the density of plasma to drop off only gradually as you move out radially from the core region toward the walls of the reactor.

The answer lies in a self-organizing process, in which the plasma creates its own barrier region – the so-called “pedestal” – that prevents particles from diffusing outward, forming a relatively sharp edge layer around the plasma.

This phenomenon was discovered in 1982 by researchers working with the ASDEX experimental tokamak in Germany. It is connected with a specific plasma state (or regime), now called the “H-mode.” (“H” stands for “high confinement.”) Researchers have since learned how to “nudge” the plasma into this H-mode routinely.

In our discussion, Fernanda Rimini called the existence of the H-mode “a kind of miracle.” Operating tokamaks in this mode dramatically increases their ability to confine the plasma. Together with breakthroughs in computer modeling and the advent of high-temperature superconductors, experience with the H-mode is a major source of confidence that tokamak reactors can become economically viable sources of energy in the future.

As is usual in plasma physics, turbulence and instabilities occur – called “edge localized modes (ELMs)” – which can cause plasma to “leak out” into the surroundings. This is a huge topic in fusion today and one of the focal points of work on the JET. JET scientists have developed special diagnostic systems to study the edge and “pedestal” region of the plasma.

Interestingly, the strategy is not to suppress the ELMs completely but, rather, to control them in such a way that a small amount of plasma can move out of the bulk of the plasma into the so-called divertor region, where impurities and helium nuclei (the “ash”) produced by the fusion reactions are removed.

In this way one can keep the core plasma “clean.” Rimini remarked that we don’t want large perturbations, only “nice little ones”.

Yes, fusion does produce some radioactivity

Moving on, I raised the issue of radioactivity in connection with operation of fusion power plants.

The first generation of fusion power plants based on the tokamak design will almost certainly employ a mixture of deuterium (D) and tritium (T) as their fuel. While deuterium is a stable isotope, tritium is radioactive. Additional radioactivity arises through the absorption of neutrons, produced in the D-T reaction, by atoms in the materials in the proximity of the fusion plasma.

Fusion power plants based on D-T fuel will use significant amounts of tritium. The walls of the vacuum chamber, as well as adjacent components and materials, will be subjected for long periods to intensive neutron bombardment. Radioactivity becomes a significant issue – albeit nothing remotely comparable to the hazards posed by the long-lived radioactive isotopes produced in fission reactors.

The first issue concerns safe operation and especially the maintenance of a D-T fusion reactor. In this context, JET is providing useful experience, especially with regard to maintenance operations that have to be carried out the radioactive environment of the reactor.

JET was designed from the very beginning for all maintenance to be done by remote control. Dr. Rimini took me to see a full-scale industrial mockup of the JET reactor vessel, where I could see one of the two 12-meter-long, remotely-operated boom systems, which are introduced through entry ports during shut-down periods. The booms are articulated in such a way that they can reach all locations inside the toroidal vacuum chamber, through snake-like motions.

Readers can see an impressive video here.

I could also view operators training on these systems. Their situation is a far cry from that of traditional mechanical “hot cell” manipulators where the operator stands just outside the cell, separated by a protective window.

In the case of JET (as in future fusion plants) the operators are situated far from the reactor, working with remote robotic arms and closed-circuit video. Most remarkable, this system provides haptic feedback – operators can “feel” objects they are handling. I saw an operator practice picking up a screw and screwing it into a hole.  

Near the JET building, UKAEA has a separate facility called RACE (Remote Applications in Challenging Environments) devoted to the further development of robotic systems for various applications, including fully autonomous robots.

Most of the time JET has operated with deuterium alone, producing only a very small number of fusion reactions. But JET has twice operated for extended periods with D-T fuel. A third and final “campaign” of experiments, designated DTE3, is being prepared now. It will run for seven weeks.

Fernanda Rimini told me that the focus of DTE3 is not to go for a new record in fusion reactions, but rather to develop plasma science, materials science, and “neutronics.”

Lessons for the future of fusion power

The latter field, which deals with the effect of neutrons on various materials, has enormous importance for future tokamak power plants. Firstly, exposure to a heavy flux of neutrons degrades materials in the reactor, and frequent replacement can be a major cost factor. A second important issue for future reactors is the effect of neutron bombardment on the performance of the superconducting coils.

A third major issue, as I shall discuss below, is how to deal with the radioactivity produced by the absorption of neutrons by the reactor vessel and surrounding components.

A main aim of the 36 planned DTE3 experiments is to investigate the impact of neutrons on in-vessel materials, electronic components and data acquisition systems. In addition, it is essential to ascertain the amount of radioactive tritium absorbed by the walls of the vacuum vessel, and to develop improved methods for reducing the heat load on reactor components, especially the divertors.

According to the plan, JET will be decommissioned after the completion of DTE3. This process, to be carried out under the auspices of the UKAEA , will provide many valuable lessons and experience for the future large-scale application of fusion energy, as well as data relevant to estimating the complete life-cycle cost of fusion power plants.

The entire JET facility, including the reactor system with all its components and auxiliary facilities, will have to be taken apart or demolished. The resulting material  – a significant portion of which will be radioactive – must be safely disposed of and the site cleared.

Unlike nuclear fission, the D-T fusion reaction itself produces no radioactive waste; the reaction products are the stable element helium-4 plus a neutron. Nearly all the neutrons are absorbed into materials and the remaining “free” neutrons decay within a few minutes.

The “radioactive waste” from the fusion reactor consists of reactor materials that have become radioactive as a result of neutron absorption, plus a small amount of radioactive tritium (half-life 12.4 years) which has been absorbed into reactor materials in the course of operation.

Ideally, provided certain chemical elements can be avoided in the composition of the materials from which the reactor is built, future D-T fusion power plants will produce only low-level waste, which does not necessitate permanent underground deposition.

Fortunately, there is significant leeway in the choice of materials in the design of fusion reactors. But it may well prove to be impossible or impractical to avoid at least a small amount of intermediate-level waste, which will require long-term storage. A short overview of these issues by the UK Committee on Radioactive Waste Management can be found here.

As far as low-level fusion waste is concerned, a number of options are being explored including recycling for commercial use in the nuclear industry and other areas.

A big advantage of fusion waste is that it consists of relatively few radioactive elements, whereas fission generates a large number of isotopes scattered across the periodic table. On the other hand, large-scale use of fusion power plants will generate low-level waste in very substantial amounts. The reuse of materials and sites is thus an important consideration.  

In the case of JET, which will have operated with D-T fuel only for periods in the range of several weeks, the level of radioactivity will be much smaller than in future power plants. Nevertheless, practically all steps of the on-site decommissioning will have to be carried out by remote control and robotic systems.

That includes dismantling of the reactor and all its auxiliary equipment, processing for removal of absorbed tritium (detritiation), cutting and sorting, waste treatment and transfer of radioactive and non-radioactive materials into containers for storage and transport.

In 2022 the UKAEA launched a new program called the “JET Decommissioning and Repurposing (JDR) program.” JDR is already begun to solicit industrial partners.

I should remind the reader that the spherical tokamak design, which the UK Atomic Energy Authority has cleverly adopted as the mainstay of its magnetic confinement fusion program, differs greatly from JET as well as from the giant ITER reactor under construction. (ITER is in many ways a scale-up of JET.)

Nevertheless, the knowledge, experience and technology generated by the JET project have been an essential input to the UK program. I think it is fair to say that JET has been one of the most successful fusion experiments so far.

NEXT: The spherical tokamak story

Jonathan Tennenbaum, PhD (mathematics), is a former editor of FUSION magazine and has written on a wide variety of topics in science and technology, including several books on nuclear energy.

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