Riemann's Contribution to Flight and Laser Fusion

Question: In some of the research I've done in plasmaphysics, your work in magnetohydrodynamics in the 1950son vortex formation is very important. How did that workstart—the work you did on plasma or magnetohydrodynamicvortex motion? That work seems very different fromaerodynamics.Yes, but it was a new subject, and in research you haveto keep up to date when you are a senior research man.Therefore, I had seminars with people who worked onthis problem. You see, at first I was an electrical engineer,because when Germany lost the First World War, I tookevery subject that I thought was important for Germany.Therefore, I studied electrical engineering too, includingelectrical physics. My physics teacher in the TechnischeHochschule (high school) was very nice to me and taughtme everything about relativity, which was new at thattime. I studied it in 1923-24. I had learned fluid dynamicsmore from electricity, and, therefore, when they startedthis magnetohydrodynamics, I would go back and do itthe proper way. I mean that electricity is not a real flow,but for magnetism, you need electricity. And that was myold subject, which I used to compare hydrodynamics withelectricity. Therefore, it was easy for me to be the boss ofthe magnetohydrodynamics seminar in Langley Field.You see, when you begin a new subject, the youngpeople have no prior experience; they've learned it onlyfrom books, but I could compare it with the things I hadlearned before and played with already, so I could be animportant man in this seminar.Question: What relation do you see between the researchon vortex motion and shock waves?The electricity had no shocks. I don't know; we nevermade a real application. There were other NASA centersthat were working on magnetohydrodynamics. I workedon magneto only for a short time, and then I came toBoulder in order to make this a center of excellence inaerospace. Well, the space things were so important thatwe worked on vortices only on the side. We had to makereal space progress.Question: Did you work with von Braun on space rocketsand that kind of thing?No. He was in another area. I was in Langley Field,where we did see supersonic parts and things like thatwhere they built the equipment for Langley. Magneto wasjust a side subject that we worked on. You see, when youwork on the same chapter day and night, you get yourselfinto a corner. Sometimes you are better off if you leaveit and come back after a week and you say, why didn't Isee this before? Of course, when it's a very importantsubject, and has to be done by October, say, you can't gointo something else at night. At Langley we sometimeshad to work on a certain problem that they gave us, andsometimes in between we had a little bit of time off, sothat we were not stuck on the same old thing. Very oftenNASA asked us to tell them about supersonics or abouthow to get out to space. The different space researchcenters didn't get money for everything. They had aspecial subject matter in which they had to prove theycould work well. We worked in this aerodynamics business,what goes into space and gets out of orbit into theatmosphere. As for rockets, of course, it was von Braun'sproblem in Houston. Some guidance people were somewhereelse—at the Ames Research Center, I think.But when von Braun had a question about supersonicdrag or lift or whatever, or whether the proper flowswould come automatically or had to be readjusted, ofcourse he would direct the question to the Langley Center.Question: How long were you at NASA?I was with NASA from 1947 to 1964, and then I camehere, to the aerospace section of the University of Colorado.My problem was that because I had secret information,I was not allowed at Langley to tell the Germansto give me my earned retirement pension. They told methat I couldn't be dependent on a foreign government. Iwas to be retired from Langley Field not later than age 70,but before I reached their retirement age, I accepted theinvitation of the University of Colorado to come and holda "lifetime" job.Adolf Busemann: A TributeBusemann was a giant in the field of aerodynamics. He was able to use applied mathematics and simplegeometrical constructions to solve the most complicated of nonlinear aerodynamic and fluid dynamic problems.For example, he created the now-famous Busemann "apple curve"—mathematical-geometrical constructions thatvery cleverly allow you to follow isentropic flows through parameter space. At Langley Field, where he was chiefscientist, Busemann taught dozens of classes in many areas—kinetic theory, electrodynamics, the physics of aerodynamicsand applied mechanics. He was able to take very complicated physics problems and draw analogies tosimpler mathematical systems, which could then be solved. If you were to ask Busemann, he would tell you thatTheodor von Karman was one of the greatest aerodynamicists of this century. Yet von Karman was a generalist; heworked in a number of areas of applied mechanics. Busemann worked in fewer areas, but his physical insights faroutshone those of others in the field.—Dr. William Grossman, research professor of plasma science, New York University, Courant Institute ofMathematical Science.On Nov. 5,1981, the Fusion Energy Foundation will honor Adolf Busemann and his work in a special dinner andaward ceremony in New York City. We would appreciate letters and greetings for presentation at the event fromreaders who worked with Busemann.October-November 1981 FUSION 41