| Title | Russia is Powering Up a Giant Laser to Test its Nukes | |
| Date | Tuesday March 14 2023, @10:20PM | |
| Author | janrinok | |
| Topic | ||
| from the dept. | ||
To check that atomic weapons work, scientists run simulations of explosions using high-energy lasers—and Russia is building the strongest one of all:
In town of Sarov, roughly 350 kilometers east of Moscow, scientists are busy working on a project to help keep Russia's nuclear weapons operational long into the future. Inside a huge facility, 10 storeys high and covering the area of two football fields, they are building what's officially known as UFL-2M—or, as the Russian media has dubbed it, the "Tsar Laser." If completed, it will be the highest-energy laser in the world.
High-energy lasers can concentrate energy on groups of atoms, increasing temperature and pressure to start nuclear reactions. Scientists can use them to simulate what happens when a nuclear warhead detonates. By creating explosions in small samples of material—either research samples or tiny amounts from existing nuclear weapons—scientists can then calculate how a full-blown bomb is likely to perform. With an old warhead, they can check that it still works as intended. Laser experiments allow testing without letting a nuke off. "It's a substantial investment by the Russians in their nuclear weapons," says Jeffrey Lewis, a nuclear non-proliferation researcher at the Middlebury Institute of International Studies in California.
Until now, Russia has been unique among the best-established nuclear powers in not having a high-energy laser. The United States has its National Ignition Facility (NIF), currently the world's most energetic laser system. Its 192 separate beams combine to deliver 1.8 megajoules of energy. Looked at in one way, a megajoule is not an enormous amount—it's equivalent to 240 food calories, similar to a light meal. But concentrating this energy onto a tiny area can create very high temperatures and pressures. France meanwhile has its Laser Mégajoule, with 80 beams currently delivering 350 kilojoules, though it aims to have 176 beams delivering 1.3 megajoules by 2026. The UK's Orion laser produces 5 kilojoules of energy; China's SG-III laser, 180 kilojoules.
If completed the Tsar Laser will surpass them all. Like the NIF, it's due to have 192 beams, but with a higher combined output of 2.8 megajoules. Currently, though, only its first stage has launched. At a Russian Academy of Sciences meeting in December 2022, an official revealed that the laser boasts 64 beams in its current state. Their total output is 128 kilojoules, 6 percent of the planned final capability. The next step would be testing them, the official said.
[...] In experiments, these lasers blast their target materials into a high-energy state of matter known as plasma. In gases, solids, and liquids, electrons are usually locked tight to their atoms' nuclei, but in plasma they roam freely. The plasmas throw out electromagnetic radiation, such as flashes of light and x-rays, and particles like electrons and neutrons. The lasers therefore also need detection equipment that can record when and where these events happen. These measurements then allow scientists to extrapolate how a full warhead might behave.
[...] Researchers have used lasers in nuclear weapons testing since at least the 1970s. At first they combined them with underground tests of actual weapons, using data from both to build theoretical models of how plasma behaves. But after the US stopped live-testing nuclear weapons in 1992 while seeking agreement on the Comprehensive Nuclear-Test-Ban Treaty, it switched to "science-based stockpile stewardship"—namely, using supercomputer simulations of warheads detonating to assess their safety and reliability.
But the US and other countries following this approach still needed to physically test some nuclear materials, with lasers, to ensure their models and simulations matched reality and that their nukes were holding up. And they still need to do this today.
[...] But Tikhonchuk [emeritus professor at the Center for Intense Lasers and Applications at the University of Bordeaux, France] believes that Russia will struggle now because it has lost much of the expertise needed, with scientists moving overseas. He notes that the Tsar Laser's beam arrays are very large, at 40 centimeters across, which poses a significant challenge for making their lenses. The larger the lens, the greater the chance there will be a defect in it. Defects can concentrate energy, heating up and damaging or destroying the lenses.
The fact that Russia is developing the Tsar Laser indicates it wants to maintain its nuclear stockpile, says Lewis. "It's a sign that they plan for these things to be around for a long time, which is not great." But if the laser is completed, he sees a sliver of hope in Russia's move. "I'm quite worried that the US, Russia, and China are going to resume explosive testing." The Tsar Laser investment might instead show that Russia thinks it already has enough data from explosive nuclear tests, he says.
| Links |
printed from SoylentNews, Russia is Powering Up a Giant Laser to Test its Nukes on 2024-04-23 20:35:19