主题：【讨论】求教物理大牛:西工大在搞天顶星技术？ -- billhy
Mr. Shawyer claims his new drive will put existing ion drives to shame. Rejected by the Australia, Britain, and U.S. firms, he's developing his ideas in China. (Source: New Scientist)
A prototype of the drive is seen here. It uses a tapered cavity to supposedly produce thrust. Despite scathing criticism in the research community, China is investing big in the technology, hoping it will give them a military edge. (Source: Wired)
China Building Electromagnetic Drive (Emdrive)
DailyTech has reported on plenty of exotic propulsion technologies. From plasma engines to laser engines, the field of space propulsion is full of quirky ideas, many with big financial backing from NASA. Thus it takes a really strange idea to stand out. The story of Roger Shawyer and his "direct electricity" rocket is such a story.
Roger Shawyer's began his career entirely within the system. He worked his way up through the ranks and eventually became a senior aerospace engineer at Matra Marconi Space (later part of EADS Astrium) in Portsmouth, UK. There he supervised the design of radar and communications systems. Mr. Shawyer even served as a consultant on the Galileo project, Europe's satellite navigation system.
Then he came up with an idea that many would call crazy.
He drew up plans for an exotic space engine unlike any the world had seen. It would use a relativistic trick, first envision by Allen Cullen in the 1950s, to convert electricity into microwaves, which would then provide a supposedly incredible thrust. At Astrium, his outlandish ideas were met with scorn. He recalls, "I was told in no uncertain terms to drop it. This came from the very top."
So Mr. Shawyer went rogue, leaving his cushy desk job to design his engine, the EmDrive on his own. Reportedly he succeeded. In September 2006, he announced he had created a 9 kg prototype which consumed 700 W of power and outputted 88 millinewtons of force. Then in May 2007, Eureka carried news that Mr. Shawyer claimed to have upped his rocket's capacity to 96.1 millinewtons on 300 W (an over 100 percent performance boost), and better yet the new rocket was capable of continuous operation and its microwave generator did not burn out like the last.
Mr. Shawyer claimed his device worked based on a tapered cavity. Microwaves bouncing inside this cavity would normally cancel out forces in Newtonian mechanics. However, Mr. Shawyer believed under Einstein's relativistic mechanics, the taper would cause force to build on one side. And he claimed to have proof of it. Further, by limiting microwave conversion to heat, by lining the cavity walls with superconductor, Mr. Shawyer said he could produce a 30 N thrust on a single watt, increasing the prototype's efficiency by nearly 100,000 times.
Criticism was quick to come, though. Mr. Shawyer's papers and prototypes had not been reproduced or peer reviewed, fueling skepticism. Worse yet, John Costella, a theoretical physicist and electrical engineer who works for the Australian Department of Defense, whose Ph.D. is in relativistic electrodynamics, the field that Mr. Shawyers research draws upon, blasted the drive in an article in the magazine New Scientist, after Mr. Shawyer submit a paper for it.
Professor Costella stated in his scathing review, "It is well known that Roger Shawyer's 'electromagnetic relativity drive' violates the law of conservation of momentum, making it simply the latest in a long line of 'perpetuum mobiles' that have been proposed and disproved for centuries. His analysis is rubbish and his 'drive' impossible."
Ostracized in the U.S., in Europe, and in Australia, Mr. Shawyer turned to a country with ambitious space goals of its own and a penchant to think outside of the box -- China. Satellite Propulsion Research (SPR), Mr. Shawyer's company, has worked out a lucrative new deal with the Chinese government to develop the tech. What's more, Chinese physicists assisting Sawyer claim they are developing theoretical simulations that will "prove" the drive works.
Mr. Shawyer recently was interviewed by Wired magazine's "Danger Room" column and stated, "NPU started their research program in June 2007, under the supervision of Professor Yang Juan. They have independently developed a mathematical simulation which shows unequivocally that a net force can be produced from a simple resonant tapered cavity. The thrust levels predicted by this simulation are similar to those resulting from the SPR design software, and the SPR test results."
He goes on to say that the Northwestern Polytechnical University (NPU) in Xi'an, a leading government controlled Chinese university is manufacturing a prototype of his device. Professor Yang confirmed this, stating, "I could confirm that our mathematical simulation gives the results Dr. Roger Shawyer told you. Now we are submitting our result to a journal. It is now under the consideration of the editor. We also developed a tapered cavity and are preparing an experiment which will be completed at the end of this year."
The new drive, if it indeed works, would not help with launching objects into space. What it would be useful for is in-space propulsion. Most sci-fi writers envisioned "sublight" engines, and the direct electricity drive would do precisely that. If the Chinese get it working, it will give them a distinct military edge in space. A flight to Mars might take only 41 days. Further, it will cut the weight and costs of satellites approximately in half, as satellites require heavy boosters to maintain orbit. In short, the drive would revolutionize much of spaceflight and give China the dominance it dreams of -- if it works.
Mr. Shawyer says he would like to deal with the U.S. as well, but says communications have died. He states, "the flight thruster program is on hold for the present. [O]nce the U.K. government had provided an export license for a U.S. military application, the major U.S. aerospace company we had been dealing with stopped talking to us."
Meanwhile he and the Chinese are awaiting the peer review of their research. And the real test will not be in the response, which has already evoked mixed opinions, but simply whether the prototypes work -- and whether China's expensive and radical gamble in one man's rebellious dream has paid off.
中国的研究者声称，他们已经证实了“不可能”的太空驱动器背后的理论，并且正在建造一个太空驱动器模型。如果他们是对的，这将改变卫星发射的经济格局，为空间探索开辟新的可能，并赋予中国的太空军事决定性的优势。
“"Emdrive”(electromagnetic drive的缩写，也就是电磁驱动)概念备受争议。创造了一概念的英国科学家Roger Shawyer认为，Emdrive能把电力通过微波转变为推进力并不违背物理定律。但很多科学家不这样认为。《新科学家》刊载的一篇关于Emdrive的文章引来了众多批评，科学家们认为Shawyer的工作明显不可能，推理也是错误的，还认为这篇文章根本不应该登出来。
“Roger Shawyer的‘电磁相对论驱动’违背了动量守恒定律，是不断提出来又不断被否定的永动机的最新版本，”澳大利亚物理学家John Costella写道，“他的分析都是垃圾，这种驱动是不可能的。”
Shawyer坚定维护自己的理论。他的公司——人造卫星推进研究公司(SPR)，已经造出了引擎的原型，用一个充满微波的锥形共振腔制造推进力。他坚持认为这并非永动机，也没有违反能量守恒定律，因为驱动器和里面的微波使用不同的坐标系。Shawyer说他最大的挑战是要让人们真正了解他的观点，而不是简单地予以否定。
一般来说这种大胆的断言通常都是由一些自学成才的山寨发明家做出的，他们声称爱因斯坦是错的。但是Shawyer为欧洲太空企业EADS Astrium工作，是个研究雷达和通信系统的项目经理。他的理论以爱因斯坦的理论为前提，推进器原理也是相对论效应的结果，在经典牛顿物理学范围不适用。许多人由于不认同他的工作而离开，英国政府的赞助也停止了。他通过美国和中国的一些投资维持，现在中国西安的西北工业大学终于等到结果了。
“西北工业大学在2007年6月启动了这个研究项目，负责人是杨娟(音译)教授。他们独立开发了一个数学模型，能够清晰证明简单的锥形共振腔能产生合力。” Shawyer告诉作者，“这一模型得出的推进力水平和SPR设计的软件得出的结果一致。”而且，西北工业大学“正在制造”基于这一理论的“推进器”。
“我能保证我们的数学模型能给出Roger Shawyer博士告诉你的结论。我们正把研究结果递交到专业期刊上，编辑们正在审阅，”杨教授补充道，“我们还开发出了锥形腔，正在为今年底的试验做准备。”
不言而喻，独立的实验结果很重要——虽然很多人想在相关的杂志上看到论文发表，但我怀疑什么时候争论才能停止都还不一定。杨教授在这一领域积累了很多经验，以前也曾作过微波等离子推进的研究，这一研究是用共振腔加速等离子喷射，从而产生推进力。虽然Emdrive背后的理论各不相同，构建硬件的工程基础却是类似的。中国必须判断推进器是否能真正工作，还是只是试验错误而产生的结论。
虽然机器产生的推进力很小，但意义重大。Shawyer把C-Band Emdrive和NASA现在使用的NSTAR等离子推进器相比较：Emdrive产生85mN的推进力，而NSTAR产生92mN(差不多是一盎司的三分之一)。但Emdrive仅消耗不到7公斤重的能量，是NSTAR30多公斤的四分之一。推进物是最大的区别：NSTAR每小时消耗10g，Emdrive却不消耗推进物。只要有电能提供，Emdrive就能不停运行。
如果试验成功，影响将是很大的：以往，人造卫星在能量消耗殆尽时就停止运行，现在的寿命将会大大延长，并能够按照指定程序运行(我们也不必因为有毒燃料的威胁而要射落卫星)。外层空间探测器将走的更远更快——直到抵达目的地。Shawyer计算一个太阳能驱动的Emdrive可以在41天内完成载人火星任务，当然，这是在正常工作的前提下。
中国会如何利用这个技术？可能由于杨教授和军方有关，他发表了一篇名为“等离子体攻击低轨道间谍卫星(Plasma Attack Against Low-Orbit Spy Satellites)”的论文。
与此同时美国如何考虑？Shawyer告诉作者，“飞行推进项目还处于观望中。一旦英国政府提供出口许可给美国军方应用，我们所接触的主要的美国宇航企业将会停止与我们对话。”
这些公司可能会认定Emdrive无法工作。如果他们错了，中国就会在主宰太空的技术方面领先至少一年，以前的卫星就会像蒸汽时代的航船一样落伍。
杨涓(1963-),女,西北工业大学副教授、博士,主要从事火箭发动机和等离子体应用的研究.
局域环境中微波等离子体电子密度诊断实验研究 物理学报 2008/03
2 自由分子流微电热推力器(FMMR)流动模拟与喷嘴型面分析 固体火箭技术 2008/02
3 自由分子流微电热推力器流动模拟与性能预示 中国空间科学技术 2008/02
4 真空中微波等离子体喷流电子数密度分布规律实验研究 物理学报 2007/01
5 磁化等离子体对电磁波反射系数的计算分析 火力与指挥控制 2007/01
6 100W微波等离子推力器固态源研制 固体火箭技术 2007/02
7 MPT在探月中的应用方案初探 固体火箭技术 2007/03
8 水工质微波电火箭能量吸收转换机理分析 机械科学与技术 2007/08
9 有约束边界的微波等离子体喷流电子数密度分布规律实验研究 西北工业大学学报 2007/05
10 真空中不同极化电磁波在微波等离子体喷流中的衰减特性实验研究 物理学报 2007/12
等离子体干扰低轨道侦察卫星的计算分析
研究等离子体干扰破坏低轨道侦察卫星功能的效应 ,提出了用等离子体反卫星的概念。对等离子体环境中卫星充放电机理及效应进行了分析 ,给出其干扰破坏低轨道卫星的途径为 :等离子体使卫星表面形成电弧放电电位差 ,并产生强烈的电弧电流和电磁脉冲 ,从而破坏太阳能电池阵、表面温控材料、星上微波电子仪器 ,并影响天线正常工作。把卫星表面分成 1 4个不同的等效单元 ,利用等效充电模式 ,计算了高密度低能和中等能量等离子体对某卫星表面的充电过程 ,分析电子温度和数密度、卫星表面初电位、太阳能电池阵电位对卫星表面最后达到平衡电位的影响。获得的结论是 :30 0 e V以上的能量将使卫星表面形成放电电位差
如果能够成功，绝对具有划时代的意义。
牛比之处在于，不消耗任何物质，只消耗能量。凭空推进，靠.......
粗一想又觉得不靠谱，任何力都是有反作用的，这玩艺不依靠任何物质的相互作用，就能凭空位移？
只靠能量，就能改变自己在空间的位置，并且没有任何后果？貌似不太可能。要不就是它确实有什么东西从系统里传递到系统外？
呵呵，这个就是电磁场约束的离子推进，这东西先天性爆发力就不足.这种推进技术只能做长时间小推力，适合深空探测.只有中美在搞，欧洲搞得还是初级的高压电直接电离，中国搞着东西都很多年了，很多科学实验卫星也试验过！
欧洲的军用航天根本就不入流，大型固体火箭基本不会造，法国的远程导弹才刚开始试验，而其他国家根本不行——英国干脆买的美国三叉戟！！！至于多弹头技术，大型固体火箭轻型化技术以及机动发射技术等，欧洲都是空白，这军用航天方面，欧洲和我们差距很大！！！既是民用航天方面，他们火箭技术和我们也是一个水平，载人航天他们是空白，深空探测比我们稍好，也仅仅进行了有限数次超越月球距离的探测！他们的月球探测计划也不如我国完善！
只要有加速度，那么足够长的时间就能达到可怕的速度。这在太空中长时间旅行，实在太有利了，呵呵。
没有远大理想的国家是不可能去搞这个技术的。估计探索火星可能都用不到这个技术吧。
一束光打到一个表面上是有压力是，只不过非常弱，光是电磁波，微波也是
理论上光帆是星际航海的有效办法。
根据现有的信息，基本是不可行的。
消耗物质产生电能，电能转化为光子，光子可以推进物体的，记得教科书里验证光压的真空里的小风车么
但是如果想靠太阳能维持在太阳系内的轨道，恐怕不行
太阳的光子打在太阳能电池板上，飞船连同太阳能电池板获得远离太阳的动量
从太阳能到EMDriver推进器的效率肯定小于100%，所以，推力肯定小于太阳光对太阳能电池板的推力
飞船只能向太阳外侧方向走