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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.
T. Shimozuma, M. Yokoyama, K. Ida, Y. Takeiri, S. Kubo, S. Murakami, A. Wakasa, H. Idei, Y. Yoshimura, T. Notake, S. Inagaki, N. Tamura, K. Toi, N. Ohyabu, M. Osakabe, K. Ikeda, K. Tsumori, Y. Oka, K. Nagaoka, O. Kaneko, I. Yamada, K. Narihara, Y. Nagayama, S. Muto, K. Tanaka, T. Tokuzawa, S. Morita, M. Goto, M. Yoshinuma, H. Funaba, T. Morisaki, K. Y. Watanabe, J. Miyazawa, T. Mutoh, T. Watari, K. Ohkubo, LHD Experiment Group
Fusion Science and Technology | Volume 58 | Number 1 | July-August 2010 | Pages 38-45
Chapter 3. Confinement and Transport | Special Issue on Large Helical Device (LHD) | doi.org/10.13182/FST10-A10791
Articles are hosted by Taylor and Francis Online.
Core electron-root confinement (CERC), observed in the Large Helical Device as well as in other helical devices, is an improved electron energy confinement mode. It is characterized by a highly peaked electron temperature profile in the core region and appears when the centrally focused electron cyclotron resonance heating power exceeds a certain threshold value. This threshold value has been clarified to associate with the transition of the radial electric field (Er) from the ion root (small negative value) to the electron root (large positive value greater than a few kV/m), based on the bifurcation nature of Er due to the ambipolarity condition of neoclassical transport fluxes that is specific in nonaxisymmetric configurations. It has been experimentally recognized that a steeper Te gradient is realized with a clear transition (power threshold nature) in target plasmas with counter neutral beam injection (NBI) than ones with codirectional NBI. It has been interpreted, based on the heat pulse propagation experiment, to be related to the rational surface or the island induced by the NBI-driven current. Transport analyses have shown that the incremental thermal diffusivity of electron heat transport becomes lower, and the standard thermal diffusivity decreases with the increase of heating power in CERC plasmas.