能源聖杯：核融合付諸實用 Mar 12, 2007 《紐時周報全文精譯》能源聖杯：核融合付諸實用 Practical Fusion, or Just a Bubble? 張佑生 譯 洛杉磯加大物理所研究生布萊恩‧卡帕斯蓋住一管透明的圓筒，不讓裡面 清澈液體產生的一些氣泡逸出。他鉗緊圓筒，筆直放在一個小旋盤上，開始旋 轉。輕彈另一個開關，每秒50次的上下強力震動開始搖晃圓筒。 LOS ANGELES － Brian Kappus, a physics graduate student at the University of California, Los Angeles, tipped the clear cylinder to trap some air bubbles in the clear liquid inside. He clamped the cylinder, upright, on a small turntable and set it spinning. With the flip of another switch, powerful up-and-down vibrations, 50 a second, started shaking the cylinder. 一顆氣泡漂浮在磷酸液上，氣泡發光，變成一顆像迷你恆星的強烈光球。 A bubble floating in the liquid － phosphoric acid － started to shine, brightening into an intensive ball of light like a miniature star. 閃亮的氣泡並未產生任何顯著的能量，但有朝一日也許會，就像一顆恆星 。一些小公司和特立獨行的大學實驗室，包括由物理學教授賽斯．普特曼主持， 位於加州校園的這間實驗室，要為未來的能源追求異想天開的解決之道：用桌 面就能搞定的裝置開發太陽的能量，也就是熱核融合反應。 The shining bubble did not produce any significant energy, but perhaps someday it might, just like a star. A few small companies and maverick university laboratories, including the one on this California campus run by Seth Putterman, a professor of physics, are pursuing quixotic solutions for future energy, trying to tap the power of the Sun－ hot nuclear fusion － in devices that fit on a tabletop. 普特曼的做法是利用被稱為聲核融合，或氣泡核融合的聲波，使溶液中的 微小氣泡膨脹破碎，產生超高溫。當溫度夠高時，原子真的能融合並釋出比核 分裂還大的能量。目前核能電廠和核子武器都運用核分裂。 Dr. Putterman’s approach is to use sound waves, called sonofusion or bubble fusion, to expand and collapse tiny bubbles, generating ultra hot temperatures. At temperatures hot enough, atoms can literally fuse and release even more energy than when they split in nuclear fission, now used in nuclear power plants and weapons. 普特曼尚未在實驗中達成核融合。他和其他科學家致力將小規模的桌上型 核融合裝置轉換成可用的系統。雖然距離成功仍很遙遠，原理卻似乎很扎實。 Dr. Putterman has not achieved fusion in his experiments. He and other scientists are devoted to turning small-scale desktop fusion into usable systems. Although success is far away, the principles seem sound. 「脈衝裝置」是加州草谷小鎮一家小公司，和普特曼同樣在探索聲波驅動 的核融合。總裁泰希恩坦承，公司的投資風險很高，但潛在收益也高。 Impulse Devices, a small company in the small town of Grass Valley, California, is exploring the same sound-driven fusion as Dr. Putterman. Its president, Ross Tessien, concedes that Impulse is a high-risk investment, but the potential payoffs are high. 「你解決了全球的汙染問題，」泰希恩表示，「你消除戰爭的必要性。你 排除燃料的匱乏。又剛好很有市場價值。就道德觀點來看，一切誘因都齊了。」 “You solve the world’s pollution problems,” Mr. Tessien said. “You eliminate the need for wars. You eliminate scarcity of fuel. And it happens to be a very valuable market. So from a commercial point of view, there’s every incentive. From a moral point of view, there’s every incentive. 四個氫原子融合為一個氦原子，是最簡單的核融合反應，使太陽這類直徑 140萬公里的氣體球變成光芒四射的恆星。但要在地球上製造能源，仍嫌太慢。 The simplest fusion reaction, four hydrogen atoms into one helium, works for turning a ball of gas like the Sun, 1.4 million kilometers across, into a shining star. But it is far too slow for generating energy on Earth. 核融合有多樣吸引力：不會產生溫室氣體，沒有放射性廢料的頭痛問題， 而且燃料充足。 The appeals of fusion are many: no planet-warming gases, no radioactive -waste headache, plentiful fuel. 「從海洋、湖泊或河川汲取的一桶水，就有相當於200加崙汽油的能量，」 泰希恩說：「這是能源科技的聖杯，人人免費使用燃料。」 “One bucket of water out of the ocean or a lake or a river has 200 gallons of gasoline worth of energy in it,” Mr. Tessien said. “It’s the holy grail of energy technologies, and everybody has the fuel for free.” 主流科學以兩種途徑追求核融合發電。一種是托克馬克裝置，用一個形如 甜甜圈的環形磁場約束電漿粒子的運動。另一個主流途徑是以雷射光束將燃料 粒向內壓縮加熱，造出導致核融合反應的溫度和密度條件。 Mainstream science is pursuing fusion along two paths. One is the tokamak design, trapping the charged atoms within a doughnut-shape magnetic field. The other mainstream approach is blasting a pellet of fuel with lasers, creating conditions hot and dense enough for fusion. 核融合一再蒙受的批評是，它許諾的願景總得在幾十年後才能實現。即使 雷射核融合和托克馬克磁場控制核融合技術上證明可行，巨大昂貴的核融合反 應器仍然可能因價格過高而沒有實用價值。 The recurrent criticism of fusion is that its promise has always been decades away. Even if lasers and tokamaks prove technologically feasible, giant, expensive fusion reactors could still turn out to be too expensive to be practical. 於是特立獨行者問：何不仔細審視某些替代方式？獨立科學家布薩德鼓吹 回歸又稱「慣性約束核融合」的法恩斯沃斯核融合反應器，使用兩個同心柵網 球形電極，加速將離子射入中心。 So the mavericks ask: Why not take a closer look at some alternative approaches? Robert W. Bussard, an independent scientist, advocates a return to the Farnswrth Fusor, otherwise known as inertial confinement fusion. It uses two electrically charged concentric spherical grids. They accelerated charged atoms, or ions, to the center. 過程中，正離子射穿中心，接近正極極板網柵時速度減緩，停止，後退， 朝中心方向落下，像彈珠在碗內滾來滾去。有時兩個離子在中心相撞並融合。 但大多數時候，離子尚未融合就撞向柵網。布薩德表示已經有移除柵網的設計。 In the process, positively charged ions fly through the center, slow down as they approach the positively charged outer grid, then stop and fall back toward the center like a marble rolling back and forth in a bowl. Sometimes two ions collide at the center and fuse. But too often the ions run into the grids before they fuse. Dr. Bussard said he had a design eliminating the grids. 布薩德自認已用慣性靜電約束法解決所有基本物理問題，而且知道如何建 造一座可運轉的核融合發電機，但大多數核融合科學家懷疑其說法。 Most fusion scientists doubt Dr. Bussard’s assertion that he has solved all the underlining physics issues with Inertial electrostatic confinement and knows how to build a working fusion power generator. 2002年，塔拉亞克漢領銜的研究人員聲稱，實現了氣泡核融合。但除了他 的實驗室，尚無其他實驗室複製其實驗，普特曼和泰希恩也無法複製那項實驗。 In 2002, researchers led by Rusi P. Taleyarkhan claimed to have achieved bubble fusion. That result has yet to be reproduced outside Dr. Taleyarkhan’s laboratories. Neither Dr. Putterman nor Mr. Tessien could duplicate that experiment. 泰希恩表示，已放棄塔拉亞克漢的方法，回到自己的設計。他有信心可以 發現核融合。「毫無疑問，核融合藏在某個系統裡。」他說：「我只要找出正 確的秘方。」 Mr. Tessien said he had abandoned using Dr. Taleyarkhan’s approach and returned to his own designs. He is confident that he will find fusion. “There is zero question that fusion is hiding in some system,” he said. “I just need to figure out the right recipe.” By KENNETH CHANG 關鍵字句 麥克阿瑟在1944年履行「我將重返」的諾言後，向菲律賓人民發表演說， 有一句是這麼說的：Follow in His name to the Holy Grail of righteous victory.（跟隨上帝之名走向代表正義勝利的聖杯。）句中的「聖杯」是耶穌 基督在最後晚餐時所用的杯（盤），曾是亞瑟王和圓桌武士追尋的目標。 本文主題在能源科技（energy technologies）中的核融合，對應的詞彙 是核分裂（nuclear fission），牽涉到原子（atom）、離子（ion）、中子 （neutron）和質子（proton）。核能電廠（nuclear power plant）、放射性 廢料（radioactive waste）和核子武器（nuclear weapons）都是常見的字彙。 特立獨行（maverick）的實驗室投入核融合研究。按maverick原意為未烙 飼主印記的小牛，a political maverick可說是政壇獨行俠。源於賽凡提斯名 著《Don Quixote》（唐吉訶德）的quixotic，比喻異想天開，浪漫到不切實 際的地步。（張佑生） 【2007-03-12/聯合報/B6版/UNITED DAILY NEWS】 ※ 編輯: precession 來自: 139.223.28.55 (03/16 09:59)