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Fusion Science and Technology
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The Frisch-Peierls memorandum: A seminal document of nuclear history
The Manhattan Project is usually considered to have been initiated with Albert Einstein’s letter to President Franklin Roosevelt in October 1939. However, a lesser-known document that was just as impactful on wartime nuclear history was the so-called Frisch-Peierls memorandum. Prepared by two refugee physicists at the University of Birmingham in Britain in early 1940, this manuscript was the first technical description of nuclear weapons and their military, strategic, and ethical implications to reach high-level government officials on either side of the Atlantic. The memorandum triggered the initiation of the British wartime nuclear program, which later merged with the Manhattan Engineer District.
A. V. Melnikov, A. Alonso, E. Ascasíbar, R. Balbin, A. A. Chmyga, Yu. N. Dnestrovskij, L. G. Eliseev, T. Estrada, J. M. Fontdecaba, C. Fuentes, J. Guasp, J. Herranz, C. Hidalgo, A. D. Komarov, A. S. Kozachek, L. I. Krupnik, M. Liniers, S. E. Lysenko, K. J. McCarthy, M. A. Ochando, I. Pastor, J. L. De Pablos, M. A. Pedrosa, S. V. Perfilov, S. Ya. Petrov, V. I. Tereshin, TJ-II Team
Fusion Science and Technology | Volume 51 | Number 1 | January 2007 | Pages 31-37
Technical Paper | Stellarators | doi.org/10.13182/FST07-A1284
Articles are hosted by Taylor and Francis Online.
The heavy ion beam probe diagnostic is used in the TJ-II stellarator to study directly the plasma electric potential with good spatial (up to 1 cm) and temporal (up to 2 s) resolution. Singly charged heavy ions, Cs+, with energies of up to 125 keV are used to probe the plasma column from the edge to the core. Both electron cyclotron resonance heating (ECRH) and neutral beam injection (NBI)-heated plasmas (PECRH = 200 to 400 kW, PNBI = 200 to 400 kW, ENBI = 28 keV) have been studied.Low-density ECRH [[over bar]n = (0.5 to 1.1) × 1019 m-3] plasmas in TJ-II are characterized by positive plasma potential on the order of 1000 to 400 V. A negative electric potential appears at the edge when the line-averaged density exceeds 0.5 × 1019 m-3. Further density rises are accompanied by a decrease in the core plasma potential, which becomes fully negative for plasma densities [over bar]n 1.5 × 1019 m-3. The NBI plasmas are characterized by a negative electric potential across the whole plasma cross section from the core to the edge. In this case, the absolute value of the central potential is on the order of -500 V. These results show a clear link between plasma potential and density in the TJ-II stellarator.