Plasma instabilities can be encountered in many branches of physics. This work focuses on relativistic plasmas with applications in theoretical astrophysics and particle accelerator physics. Even though these fields seem to be unrelated the underlying plasma physics processes are often very similar. Two plasma instabilities - the beam-beam instability and the coherent synchrotron radiation instability - are analyzed. The former severely limits the achievable luminosity in storage rings and is related to the two-stream instability which has been proposed as a candidate for the radiation mechanism of radio pulsars. The main emphasis is on coherent synchrotron radiation which can lead to prohibitive energy losses in bunch compressors. Coherent synchrotron radiation also makes up the intense emission of radio waves by pulsars. Simple models based on the linearized Vlasov equation and relativistic magnetohydrodynamics which allow to compute detailed spectra of the emitted radiation are developed.
Deep Dive into Collisionless Beam-Radiation Processes in the Laboratory and Astrophysics.
Plasma instabilities can be encountered in many branches of physics. This work focuses on relativistic plasmas with applications in theoretical astrophysics and particle accelerator physics. Even though these fields seem to be unrelated the underlying plasma physics processes are often very similar. Two plasma instabilities - the beam-beam instability and the coherent synchrotron radiation instability - are analyzed. The former severely limits the achievable luminosity in storage rings and is related to the two-stream instability which has been proposed as a candidate for the radiation mechanism of radio pulsars. The main emphasis is on coherent synchrotron radiation which can lead to prohibitive energy losses in bunch compressors. Coherent synchrotron radiation also makes up the intense emission of radio waves by pulsars. Simple models based on the linearized Vlasov equation and relativistic magnetohydrodynamics which allow to compute detailed spectra of the emitted radiation are deve
2000 he came to Cornell as a graduate student in the department of physics. He has been working on a variety of problems in theoretical physics, most notably in plasma physics (with applications in astrophysics and particle accelerator physics) and gravity. In 1998 the German National Academic Foundation (Studienstiftung des deutschen Volkes) elected him a fellow. He is also a member of the American Physical Society.
iii To the memory of Joe Rogers was actually worth doing.
It is with regret that one of my teachers could not see the completion of this work. Joseph T. Roger’s untimely death came as a surprise to many of us. In the obituary for Joe I wrote: " … I was reminded of his cheerful personality, his endless patience and of course his knowledge of physics. The former was the reason undergrads in our department used to call him “Happy Joe” (I doubt he was actually aware of this, though) … Unfortunately, there is not much I can do except express my sincere condolences to Joe’s family once again. I was rather fortunate to have met Georg H. Hoffstaetter who helped me finish a paper on the beam-beam interaction in storage rings which I started writing together with Joe before he was diagnosed with terminal cancer. Georg’s passion and enthusiasm for particle accelerators can become contagious and it simply will not stop -even when rowing across a / the Lost Lake somewhere in Oregon during heavy snowfall.
There is a huge number of support staff that struggled with my problems and they deserve being mentioned: Lori Beyea-Powers (accounting), Cora Jackson (travel arrangements), Joyce Oliver (accounting), Rosemary French (support for teaching), Tom Shannon (IT), Chuck Jessop (licensing) and many more. There is one person though I have to list separately. Of course I am talking about Debra Hatfield. The list of services she provided me with is so long that I will not even attempt to mention all the things she has done for me. I am just stunned by Deb’s ability to solve my everyday problems and I will miss her.
There is yet another person missing who deserves a lot of credit and this person is James W. York, Jr.! I have been extremely lucky and privileged to have met Jimmy. His insight into general relativity is almost impossible to match. Our private conversations about general relativity, quantum gravity and other (sometimes more trivial) aspects of life encouraged me to keep working on my ideas.
Finally, I would like to apologize. I have never really worked with other people together on a project so closely before. The problem with me is that I have my own ideas and ways of doing certain things. I feel very strongly about them and about how physics ought to be done. Ultimately, this makes me at odds with almost everybody, and I can only hope Cornell will find better graduate students than me who are easier to work with in the future. 3.1 Radio pulsars are spinning neutron stars with strong magnetic fields. At the magnetic poles their radiation follows the magnetic field lines. Since the field lines and the axis of rotation are misaligned the radiation sweeps out a cone. The region in which the radiation is believed to be generated is shown in gray. A similar cone could be drawn on the other side of the star. . . . . . . . . . . 3.2 The observed spectrum of the Crab pulsar extends from the radio regime to frequencies up to 10 27 Hz [1].The straight line in the radio regime is proportional to ν -5/3 . . . . . . . . . . . . . . . . . . . . 3.3 Geometry of the regions surrounding a neutron star. The closed magnetosphere is followed by a gap in which strong electric fields accelerate charged particles. The star is surrounded by a co-rotating magnetosphere which cannot extend beyond the velocity-of-light cylinder, i.e. the radius at which the velocity of the particles would exceed the speed of light at angular velocity Ω where Ω is the angular velocity of the star (and the co-rotating magnetosphere). . . cent bulbs, klystrons in microwave ovens, electron beams in CRTs, particle accelerators or electron microscopes etc. There are two recurring main questions which arise in plasma physics: How do plasmas evolve in time and are there equilibria which are stable under the influence of small perturbations? How much energy is lost due to radiation? Even though the mentioned applications do not seem to have much in common, plasma instabilities and radiation are often caused by the same few well-known (and some not so well-known) processes. This opens up possibilities for testing astrophysical processes in the laboratory.
After covering a few basics, the beam-beam instability (a rather unpleasant instability encountered in storage rings which severely limits the achievable luminosity) is reviewed. In some aspects this instability resembles the two-stream instability which is currently considered to be responsible for the radio emission of spinning neutron stars (radio pulsars). Chapter 5 deals with the Coherent
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