https://www.bastillepost.com/hongkong/a ... e%e7%9b%8a
（星島日報報道）在全球的能源需求不斷增加之下，科學家一直希望以「核聚變」（亦稱核融合）技術打造出「人造太陽」，獲得大量潔淨能源。美英媒體昨日報道，美國加州的科學家在此領域獲得「重要突破」，首次在核聚變反應中取得「能量淨增益」，即產生的能源大於消耗的能源。英國《金融時報》和《華盛頓郵報》報道，加州勞倫斯利佛摩國家實驗室（LLNL）使用實驗性質的核聚變反應爐，達成了「能量淨增益」（Net Energy Gain）。這代表研究人員首次成功在核聚變反應中，產生的能源大於消耗的能源，可望朝追求零碳能源邁出重大一步。
「人造太陽」
版主: admin1
Re: 「人造太陽」
https://www.boomlive.in/explainers/fusi ... sics-20407
So what did they accomplish? To assess the success of a fusion experiment, physicists look at the ratio between the energy released from the process of fusion and the amount of energy within the lasers. This ratio is called gain. Anything above a gain of 1 means that the fusion process released more energy than the lasers delivered. On Dec. 5, 2022, the National Ignition Facility shot a pellet of fuel with 2 million joules of laser energy – about the amount of power it takes to run a hair dryer for 15 minutes – all contained within a few billionths of a second. This triggered a fusion reaction that released 3 million joules. That is a gain of about 1.5, smashing the previous record of a gain of 0.7 achieved by the facility in August 2021. How big a deal is this result? Fusion energy has been the "holy grail" of energy production for nearly half a century. While a gain of 1.5 is, I believe, a truly historic scientific breakthrough, there is still a long way to go before fusion is a viable energy source. While the laser energy of 2 million joules was less than the fusion yield of 3 million joules, it took the facility nearly 300 million joules to produce the lasers used in this experiment. This result has shown that fusion ignition is possible, but it will take a lot of work to improve the efficiency to the point where fusion can provide a net positive energy return when taking into consideration the entire end-to-end system, not just a single interaction between the lasers and the fuel. What needs to be improved? There are a number of pieces of the fusion puzzle that scientists have been steadily improving for decades to produce this result, and further work can make this process more efficient. First, lasers were only invented in 1960. When the U.S. government completed construction of the National Ignition Facility in 2009, it was the most powerful laser facility in the world, able to deliver 1 million joules of energy to a target. The 2 million joules it produces today is 50 times more energetic than the next most powerful laser on Earth. More powerful lasers and less energy-intensive ways to produce those powerful lasers could greatly improve the overall efficiency of the system. Fusion conditions are very challenging to sustain, and any small imperfection in the capsule or fuel can increase the energy requirement and decrease efficiency. Scientists have made a lot of progress to more efficiently transfer energy from the laser to the canister and the X-ray radiation from the canister to the fuel capsule, but currently only about 10% to 30% of the total laser energy is transferred to the canister to the fuel. Finally, while one part of the fuel, deuterium, is naturally abundant in sea water, tritium is much rarer. Fusion itself actually produces tritium, so researchers are hoping to develop ways of harvesting this tritium directly. In the meantime, there are other methods available to produce the needed fuel. These and other scientific, technological and engineering hurdles will need to be overcome before fusion will produce electricity for your home. Work will also need to be done to bring the cost of a fusion power plant well down from the US$3.5 billion of the National Ignition Facility. These steps will require significant investment from both the federal government and private industry. It's worth noting that there is a global race around fusion, with many other labs around the world pursuing different techniques. But with the new result from the National Ignition Facility, the world has, for the first time, seen evidence that the dream of fusion is achievable. Carolyn Kuranz, Associate Professor of Nuclear Engineering, University of Michigan
https://www.boomlive.in/explainers/fusi ... sics-20407
So what did they accomplish? To assess the success of a fusion experiment, physicists look at the ratio between the energy released from the process of fusion and the amount of energy within the lasers. This ratio is called gain. Anything above a gain of 1 means that the fusion process released more energy than the lasers delivered. On Dec. 5, 2022, the National Ignition Facility shot a pellet of fuel with 2 million joules of laser energy – about the amount of power it takes to run a hair dryer for 15 minutes – all contained within a few billionths of a second. This triggered a fusion reaction that released 3 million joules. That is a gain of about 1.5, smashing the previous record of a gain of 0.7 achieved by the facility in August 2021. How big a deal is this result? Fusion energy has been the "holy grail" of energy production for nearly half a century. While a gain of 1.5 is, I believe, a truly historic scientific breakthrough, there is still a long way to go before fusion is a viable energy source. While the laser energy of 2 million joules was less than the fusion yield of 3 million joules, it took the facility nearly 300 million joules to produce the lasers used in this experiment. This result has shown that fusion ignition is possible, but it will take a lot of work to improve the efficiency to the point where fusion can provide a net positive energy return when taking into consideration the entire end-to-end system, not just a single interaction between the lasers and the fuel. What needs to be improved? There are a number of pieces of the fusion puzzle that scientists have been steadily improving for decades to produce this result, and further work can make this process more efficient. First, lasers were only invented in 1960. When the U.S. government completed construction of the National Ignition Facility in 2009, it was the most powerful laser facility in the world, able to deliver 1 million joules of energy to a target. The 2 million joules it produces today is 50 times more energetic than the next most powerful laser on Earth. More powerful lasers and less energy-intensive ways to produce those powerful lasers could greatly improve the overall efficiency of the system. Fusion conditions are very challenging to sustain, and any small imperfection in the capsule or fuel can increase the energy requirement and decrease efficiency. Scientists have made a lot of progress to more efficiently transfer energy from the laser to the canister and the X-ray radiation from the canister to the fuel capsule, but currently only about 10% to 30% of the total laser energy is transferred to the canister to the fuel. Finally, while one part of the fuel, deuterium, is naturally abundant in sea water, tritium is much rarer. Fusion itself actually produces tritium, so researchers are hoping to develop ways of harvesting this tritium directly. In the meantime, there are other methods available to produce the needed fuel. These and other scientific, technological and engineering hurdles will need to be overcome before fusion will produce electricity for your home. Work will also need to be done to bring the cost of a fusion power plant well down from the US$3.5 billion of the National Ignition Facility. These steps will require significant investment from both the federal government and private industry. It's worth noting that there is a global race around fusion, with many other labs around the world pursuing different techniques. But with the new result from the National Ignition Facility, the world has, for the first time, seen evidence that the dream of fusion is achievable. Carolyn Kuranz, Associate Professor of Nuclear Engineering, University of Michigan
https://www.boomlive.in/explainers/fusi ... sics-20407
Re: 「人造太陽」
https://www.nbcnews.com/science/science ... rcna61326
The most detailed news article so far.
The breakthrough will not immediately open the floodgates to clean power in American homes, but it is a powerful symbol that the fundamental scientific concepts underlying the promise of fusion are sound.
“There are a lot of scientists who said, ‘I don’t believe any of you guys. You’ll never make it work,’” said Stephen Bodner, a former director of the laser fusion program at the U.S. Naval Research Laboratory, or NRL. “Livermore showed — lo and behold — you can do it.”
U.S. Secretary of Energy Jennifer Granholm described the breakthrough as "one of the most impressive scientific feats of the 21st century.”
Engineering challenges remain that could take years or decades to work out before the technology could fuel power plants and transfer energy to the U.S. electrical grid, experts say.
While the Livermore team achieved what researchers call a scientific break-even or energy gain, it did not achieve an engineering break-even: The inefficient lasers used in the experiment required about 300 megajoules of energy to fire just 2 megajoules of energy into the experiment. The reaction produced about 3 megajoules of energy.
The reaction started and finished in about as long as it takes to blink your eyes and temperatures were roughly ten times hotter than the temperature of the sun, Livermore scientists said in a news conference.
The most detailed news article so far.
The breakthrough will not immediately open the floodgates to clean power in American homes, but it is a powerful symbol that the fundamental scientific concepts underlying the promise of fusion are sound.
“There are a lot of scientists who said, ‘I don’t believe any of you guys. You’ll never make it work,’” said Stephen Bodner, a former director of the laser fusion program at the U.S. Naval Research Laboratory, or NRL. “Livermore showed — lo and behold — you can do it.”
U.S. Secretary of Energy Jennifer Granholm described the breakthrough as "one of the most impressive scientific feats of the 21st century.”
Engineering challenges remain that could take years or decades to work out before the technology could fuel power plants and transfer energy to the U.S. electrical grid, experts say.
While the Livermore team achieved what researchers call a scientific break-even or energy gain, it did not achieve an engineering break-even: The inefficient lasers used in the experiment required about 300 megajoules of energy to fire just 2 megajoules of energy into the experiment. The reaction produced about 3 megajoules of energy.
The reaction started and finished in about as long as it takes to blink your eyes and temperatures were roughly ten times hotter than the temperature of the sun, Livermore scientists said in a news conference.
Re: 「人造太陽」
https://www.nbcnews.com/science/science ... rcna61326
The most detailed news article so far.
The breakthrough will not immediately open the floodgates to clean power in American homes, but it is a powerful symbol that the fundamental scientific concepts underlying the promise of fusion are sound.
“There are a lot of scientists who said, ‘I don’t believe any of you guys. You’ll never make it work,’” said Stephen Bodner, a former director of the laser fusion program at the U.S. Naval Research Laboratory, or NRL. “Livermore showed — lo and behold — you can do it.”
U.S. Secretary of Energy Jennifer Granholm described the breakthrough as "one of the most impressive scientific feats of the 21st century.”
Engineering challenges remain that could take years or decades to work out before the technology could fuel power plants and transfer energy to the U.S. electrical grid, experts say.
While the Livermore team achieved what researchers call a scientific break-even or energy gain, it did not achieve an engineering break-even: The inefficient lasers used in the experiment required about 300 megajoules of energy to fire just 2 megajoules of energy into the experiment. The reaction produced about 3 megajoules of energy.
The reaction started and finished in about as long as it takes to blink your eyes and temperatures were roughly ten times hotter than the temperature of the sun, Livermore scientists said in a news conference.
The most detailed news article so far.
The breakthrough will not immediately open the floodgates to clean power in American homes, but it is a powerful symbol that the fundamental scientific concepts underlying the promise of fusion are sound.
“There are a lot of scientists who said, ‘I don’t believe any of you guys. You’ll never make it work,’” said Stephen Bodner, a former director of the laser fusion program at the U.S. Naval Research Laboratory, or NRL. “Livermore showed — lo and behold — you can do it.”
U.S. Secretary of Energy Jennifer Granholm described the breakthrough as "one of the most impressive scientific feats of the 21st century.”
Engineering challenges remain that could take years or decades to work out before the technology could fuel power plants and transfer energy to the U.S. electrical grid, experts say.
While the Livermore team achieved what researchers call a scientific break-even or energy gain, it did not achieve an engineering break-even: The inefficient lasers used in the experiment required about 300 megajoules of energy to fire just 2 megajoules of energy into the experiment. The reaction produced about 3 megajoules of energy.
The reaction started and finished in about as long as it takes to blink your eyes and temperatures were roughly ten times hotter than the temperature of the sun, Livermore scientists said in a news conference.
Re: 「人造太陽」
https://www.hk01.com/%E5%8D%B3%E6%99%82 ... -%E5%9C%96
「萬物生長靠太陽，EAST擁有類似太陽的運行機制，因此有『人造太陽』之稱。」中科院合肥物質科學研究院等離子體物理研究所王騰博士説，煤、石油、天然氣未來有枯竭的危險，還存在一定的環境污染，而「人造太陽」核聚變反應所需的原材料在地球上幾乎取之不盡、用之不竭，生成物也沒有危害，被認為是理想的「終極能源」。
原文網址: 中國「人造太陽」升級改造 將挑戰1億攝氏度燃燒100秒 | 香港01 https://www.hk01.com/article/604248?utm ... m=referral
「萬物生長靠太陽，EAST擁有類似太陽的運行機制，因此有『人造太陽』之稱。」中科院合肥物質科學研究院等離子體物理研究所王騰博士説，煤、石油、天然氣未來有枯竭的危險，還存在一定的環境污染，而「人造太陽」核聚變反應所需的原材料在地球上幾乎取之不盡、用之不竭，生成物也沒有危害，被認為是理想的「終極能源」。
原文網址: 中國「人造太陽」升級改造 將挑戰1億攝氏度燃燒100秒 | 香港01 https://www.hk01.com/article/604248?utm ... m=referral
Re: 「人造太陽」
https://en.wikipedia.org/wiki/Tokamak_F ... or#General
n nuclear fusion, there are two types of reactors stable enough to conduct fusion: magnetic confinement reactors and inertial confinement reactors. The former method of fusion seeks to lengthen the time that ions spend close together in order to fuse them together, while the latter aims to fuse the ions so fast that they do not have time to move apart. Inertial confinement reactors, unlike magnetic confinement reactors, use laser fusion and ion-beam fusion in order to conduct fusion. However, with magnetic confinement reactors you avoid the problem of having to find a material that can withstand the high temperatures of nuclear fusion reactions. The heating current is induced by the changing magnetic fields in central induction coils and exceeds a million amperes. Magnetic fusion devices keep the hot plasma out of contact with the walls of its container by keeping it moving in circular or helical paths by means of the magnetic force on charged particles and by a centripetal force acting on the moving particles.[4]
History
Tokamak
By the early 1960s, the fusion power field had grown large enough that the researchers began organizing semi-annual meetings that rotated around the various research establishments. In 1968, the now-annual meeting was held in Novosibirsk, where the Soviet delegation surprised everyone by claiming their tokamak designs had reached performance levels at least an order of magnitude better than any other device. The claims were initially met with skepticism, but when the results were confirmed by a UK team the next year, this huge advance led to a "virtual stampede" of tokamak construction.[5]
In the US, one of the major approaches being studied up to this point was the stellarator, whose development was limited almost entirely to the PPPL. Their latest design, the Model C, had recently gone into operation and demonstrated performance well below theoretical calculations, far from useful figures. With the confirmation of the Novosibirsk results, they immediately began converting the Model C to a tokamak layout, known as the Symmetrical Tokamak (ST). This was completed in the short time of only eight months, entering service in May 1970. ST's computerized diagnostics allowed it to quickly match the Soviet results, and from that point, the entire fusion world was increasingly focused on this design over any other.[6]
Princeton Large Torus
During the early 1970s, Shoichi Yoshikawa was looking over the tokamak concept. He noted that as the size of the reactor's minor axis (the diameter of the tube) increased compared to its major axis (the diameter of the entire system) the system became more efficient. An added benefit was that as the minor axis increased, confinement time improved for the simple reason that it took longer for the fuel ions to reach the outside of the reactor. This led to widespread acceptance that designs with lower aspect ratios were a key advance over earlier models.[2]
This led to the Princeton Large Torus (PLT), which was completed in 1975. This system was successful to the point where it quickly reached the limits of its Ohmic heating system, the system that passed current through the plasma to heat it. Among the many ideas proposed for further heating, in cooperation with Oak Ridge National Laboratory, PPPL developed the idea of neutral beam injection. This used small particle accelerators to inject fuel atoms directly into the plasma, both heating it and providing fresh fuel.[2]
After a number of modifications to the beam injection system, the newly equipped PLT began setting records and eventually made several test runs at 60 million K, more than enough for a fusion reactor. To reach the Lawson criterion for ignition, all that was needed was higher plasma density, and there seemed to be no reason this would not be possible in a larger machine. There was widespread belief that break-even would be reached during the 1970s.[6][2]
TFTR concept
Inside the TFTR plasma vessel
After the success of PLT and other follow-on designs, the basic concept was considered well understood. PPPL began the design of a much larger successor to PLT that would demonstrate plasma burning in pulsed operation.[2]
In July 1974, the Department of Energy (DOE) held a large meeting that was attended by all the major fusion labs. Notable among the attendees was Marshall Rosenbluth, a theorist who had a habit of studying machines and finding a variety of new instabilities that would ruin confinement. To everyone's surprise, at this meeting he failed to raise any new concerns. It appeared that the path to break-even was clear.[7]
The last step before the attack on break-even would be to make a reactor that ran on a mixture of deuterium and tritium, as opposed to earlier machines which ran on deuterium alone. This was because tritium was both radioactive and easily absorbed in the body, presenting safety issues that made it expensive to use. It was widely believed that the performance of a machine running on deuterium alone would be basically identical to one running on D-T, but this assumption needed to be tested. Looking over the designs presented at the meeting, the DOE team chose the Princeton design.[7]
Bob Hirsch, who recently took over the DOE steering committee, wanted to build the test machine at Oak Ridge National Laboratory (ORNL), but others in the department convinced him it would make more sense to do so at PPPL. They argued that a Princeton team would be more involved than an ORNL team running someone else's design. If an engineering prototype of a commercial system followed, that could be built at Oak Ridge. They gave the project the name TFTR and went to Congress for funding, which was granted in January 1975. Conceptual design work was carried out throughout 1975, and detailed design began the next year.[7]
TFTR would be the largest tokamak in the world; for comparison, the original ST had a plasma diameter of 12 inches (300 mm), while the follow-on PLT design was 36 inches (910 mm), and the TFTR was designed to be 86 inches (2,200 mm).[2] This made it roughly double the size of other large-scale machines of the era; the 1978 Joint European Torus and roughly concurrent JT-60 were both about half the diameter.[8]
As PLT continued to generate better and better results, in 1978 and 79, additional funding was added and the design amended to reach the long-sought goal of "scientific breakeven" when the amount of power produced by the fusion reactions in the plasma was equal to the amount of power being fed into it to heat it to operating temperatures. Also known as Q = 1, this is an important step on the road to useful power-producing designs.[9] To meet this requirement, the heating system was upgraded to 50 MW, and finally to 80 MW.[10]
n nuclear fusion, there are two types of reactors stable enough to conduct fusion: magnetic confinement reactors and inertial confinement reactors. The former method of fusion seeks to lengthen the time that ions spend close together in order to fuse them together, while the latter aims to fuse the ions so fast that they do not have time to move apart. Inertial confinement reactors, unlike magnetic confinement reactors, use laser fusion and ion-beam fusion in order to conduct fusion. However, with magnetic confinement reactors you avoid the problem of having to find a material that can withstand the high temperatures of nuclear fusion reactions. The heating current is induced by the changing magnetic fields in central induction coils and exceeds a million amperes. Magnetic fusion devices keep the hot plasma out of contact with the walls of its container by keeping it moving in circular or helical paths by means of the magnetic force on charged particles and by a centripetal force acting on the moving particles.[4]
History
Tokamak
By the early 1960s, the fusion power field had grown large enough that the researchers began organizing semi-annual meetings that rotated around the various research establishments. In 1968, the now-annual meeting was held in Novosibirsk, where the Soviet delegation surprised everyone by claiming their tokamak designs had reached performance levels at least an order of magnitude better than any other device. The claims were initially met with skepticism, but when the results were confirmed by a UK team the next year, this huge advance led to a "virtual stampede" of tokamak construction.[5]
In the US, one of the major approaches being studied up to this point was the stellarator, whose development was limited almost entirely to the PPPL. Their latest design, the Model C, had recently gone into operation and demonstrated performance well below theoretical calculations, far from useful figures. With the confirmation of the Novosibirsk results, they immediately began converting the Model C to a tokamak layout, known as the Symmetrical Tokamak (ST). This was completed in the short time of only eight months, entering service in May 1970. ST's computerized diagnostics allowed it to quickly match the Soviet results, and from that point, the entire fusion world was increasingly focused on this design over any other.[6]
Princeton Large Torus
During the early 1970s, Shoichi Yoshikawa was looking over the tokamak concept. He noted that as the size of the reactor's minor axis (the diameter of the tube) increased compared to its major axis (the diameter of the entire system) the system became more efficient. An added benefit was that as the minor axis increased, confinement time improved for the simple reason that it took longer for the fuel ions to reach the outside of the reactor. This led to widespread acceptance that designs with lower aspect ratios were a key advance over earlier models.[2]
This led to the Princeton Large Torus (PLT), which was completed in 1975. This system was successful to the point where it quickly reached the limits of its Ohmic heating system, the system that passed current through the plasma to heat it. Among the many ideas proposed for further heating, in cooperation with Oak Ridge National Laboratory, PPPL developed the idea of neutral beam injection. This used small particle accelerators to inject fuel atoms directly into the plasma, both heating it and providing fresh fuel.[2]
After a number of modifications to the beam injection system, the newly equipped PLT began setting records and eventually made several test runs at 60 million K, more than enough for a fusion reactor. To reach the Lawson criterion for ignition, all that was needed was higher plasma density, and there seemed to be no reason this would not be possible in a larger machine. There was widespread belief that break-even would be reached during the 1970s.[6][2]
TFTR concept
Inside the TFTR plasma vessel
After the success of PLT and other follow-on designs, the basic concept was considered well understood. PPPL began the design of a much larger successor to PLT that would demonstrate plasma burning in pulsed operation.[2]
In July 1974, the Department of Energy (DOE) held a large meeting that was attended by all the major fusion labs. Notable among the attendees was Marshall Rosenbluth, a theorist who had a habit of studying machines and finding a variety of new instabilities that would ruin confinement. To everyone's surprise, at this meeting he failed to raise any new concerns. It appeared that the path to break-even was clear.[7]
The last step before the attack on break-even would be to make a reactor that ran on a mixture of deuterium and tritium, as opposed to earlier machines which ran on deuterium alone. This was because tritium was both radioactive and easily absorbed in the body, presenting safety issues that made it expensive to use. It was widely believed that the performance of a machine running on deuterium alone would be basically identical to one running on D-T, but this assumption needed to be tested. Looking over the designs presented at the meeting, the DOE team chose the Princeton design.[7]
Bob Hirsch, who recently took over the DOE steering committee, wanted to build the test machine at Oak Ridge National Laboratory (ORNL), but others in the department convinced him it would make more sense to do so at PPPL. They argued that a Princeton team would be more involved than an ORNL team running someone else's design. If an engineering prototype of a commercial system followed, that could be built at Oak Ridge. They gave the project the name TFTR and went to Congress for funding, which was granted in January 1975. Conceptual design work was carried out throughout 1975, and detailed design began the next year.[7]
TFTR would be the largest tokamak in the world; for comparison, the original ST had a plasma diameter of 12 inches (300 mm), while the follow-on PLT design was 36 inches (910 mm), and the TFTR was designed to be 86 inches (2,200 mm).[2] This made it roughly double the size of other large-scale machines of the era; the 1978 Joint European Torus and roughly concurrent JT-60 were both about half the diameter.[8]
As PLT continued to generate better and better results, in 1978 and 79, additional funding was added and the design amended to reach the long-sought goal of "scientific breakeven" when the amount of power produced by the fusion reactions in the plasma was equal to the amount of power being fed into it to heat it to operating temperatures. Also known as Q = 1, this is an important step on the road to useful power-producing designs.[9] To meet this requirement, the heating system was upgraded to 50 MW, and finally to 80 MW.[10]