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Speaker: Henry P. Freund
Topic: A Primer on the Physics of Free-Electron Lasers
Time and Location: 1:00 p.m., with Q&A to follow in 1st floor conference room B at the American Center for Physics (www.acp.org), 1 Physics Ellipse, College Park, MD-- off River Rd., between Kenilworth Ave. and Paint Branch Parkway.
Abstract: The basic concepts underlying the free-electron laser (FEL) were formulated by Hans Motz in 1950. This was followed by R.M. Philips who independently invented the Ubitron in the early 1960’s. The Ubitron was a microwave tube based on the same concepts described by Motz. However, the modern development of the FEL began in 1976 at Stanford when John Madey, who coined the term “free-electron laser”, and co-workers demonstrated operation of an infrared FEL. Since that time, FELs have undergone continuous development and now operate over spectral ranges from the terahertz band through hard x-rays. A brief historical review will be given, followed by a discussion of the fundamental concepts underlying the physics of FELs and a summary of the principal configurations employed. At the present time, there are two major lines of development: high average power oscillators, and Self-Amplified Spontaneous Emission (SASE) x-ray FELs. A discussion of the state-of-the-art of theory and simulation of FELs will be presented with an emphasis on comparisons between theory, simulation and FEL experiments.
Biography: Dr. Freund is a Fellow of the American Physical Society. He received a B.S. in Physics from Rensselaer Polytechnic Institute in 1971, and a Ph.D. in Physics from the University of Maryland in 1976. He is a theoretical plasma physicist involved in studies of coherent radiation sources such as free-electron lasers and microwave tubes by both analytical and numerical methods. He has published more than 180 papers in refereed journals, made numerous contributions to books and published proceedings, and coauthored a book entitled Principles of Free-electron Lasers [Springer, Cham, Switzerland, 2018, 3rd edition). In addition to this scholarly activity, Dr. Freund has also made contributions to more popular scientific literature with contributions on free-electron lasers published in Scientific American magazine and the Academic Press Encyclopedia of Science and Technology. Dr. Freund's work in the field of free-electron lasers includes analytic investigation of the orbital stability of relativistic electron beams in the undulator magnetic fields, the spontaneous and stimulated emission of radiation. He has developed both one- and three-dimensional nonlinear formulations of free-electron lasers, and has collaborated with experimenters at a wide range of universities, government laboratories and internationally.