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| influenced = James Hansen | footnotes = }} James Alfred Van Allen (September 7, 1914August 9, 2006) was an American space scientist at the University of Iowa. He was instrumental in establishing the field of magnetospheric research in space. The Van Allen radiation belts were named after him, following their discovery by his Geiger–Müller tube instruments on the 1958 satellites: (Explorer 1, Explorer 3, and Pioneer 3)〔(【引用サイトリンク】publisher=NASA )〕〔(【引用サイトリンク】publisher=NASA )〕〔(【引用サイトリンク】publisher=NASA )〕 during the International Geophysical Year. Van Allen led the scientific community for the inclusion of scientific research instruments on space satellites. ==Early years== Van Allen was born on 7 September 1914 on a small farm near Mount Pleasant, Iowa, the second of four sons of Alfred Morris and Alma Olney Van Allen. He grew up in the small town of Mount Pleasant, located forty-five miles due south of Iowa City. As a child he was fascinated by mechanical and electrical devices and was an avid reader of Popular Mechanics and Popular Science magazines. He once horrified his mother by constructing a coil that produced foot-long sparks and caused his hair to stand on end.〔 Van Allen was valedictorian of his high school class in 1931, and received his bachelor's degree in physics, summa cum laude, from Iowa Wesleyan College in 1935. While an undergraduate at Iowa Wesleyan, he assisted the senior scientist of the second Byrd Expedition (1934–35) to Antarctica in preparing seismic and magnetic experimental equipment. (In 2004, the American Polar Society commemorated his work by presenting Van Allen with its Honors of the Society award.) He earned his master's and doctorate from the University of Iowa in 1936 and 1939, respectively. Van Allen credits C. A. Cottrell, a science instructor in his high school, with stimulating his initial interest in science. He developed parallel interests in wood and metal crafts and did well in other subjects, becoming valedictorian of his Mount Pleasant High School class upon his graduation in June 1931. His valedictorian address was: ''Pax Romana, Pax Americana''. His slightly flat feet probably preserved Van Allen for the role that he was to play in developing the field of space science. With a strong interest in things nautical (which he retained throughout his life), he took the entrance examinations for entry into the U.S. Naval Academy while in high school. With outstanding grades, and with the backing of his local Congressman, William F. Kopp he applied for admission. All went well initially, but when he appeared for his physical examination, he was rejected for three reasons. He had flat feet, his eyesight was somewhat deficient, and he didn’t know how to swim. Thus, he was forced to pursue a different path. Immediately following high school, Van Allen went to Iowa Wesleyan College there in Mount Pleasant, majoring in physics and graduating, with a class of 38, summa cum laude in June 1935. It was at Iowa Wesleyan during the summer of 1932, after completing his freshman year, that Van Allen was introduced to geophysics research under the tutelage of Physics Professor Thomas C. Poulter. Van Allen had great admiration for this early mentor throughout his life. He stated in one of his autobiographical sketches, “Poulter, () one of the most inspiring and creative experimentalists that I have ever known before or since that time....” Poulter employed him as a summer assistant, “at 35 cents an hour, payable occasionally.” Poulter had been chosen by Admiral Richard E. Byrd as his chief scientist for the 1933-1935 Second Byrd Antarctic Expedition. He had the task of planning and conducting geophysical investigations during that expedition. Van Allen assisted Poulter in those preparations; his contributions included the development of a number of instruments, including a simple seismograph and a tilt-meter for recording the shifting of glacial surfaces. Van Allen was entrusted with the checkout of an extra sensitive field magnetometer on loan from the ''Department of Terrestrial Magnetism'' (DTM) of the Carnegie Institution of Washington, DC. In learning how to use the magnetometer and its associated theodolite, he made a magnetic field survey of Henry County, Iowa, which was included in the 1932 national grid published by the Department of Terrestrial Magnetism. Reflecting later on this magnetometer, he referred to it as, "...the most beautiful instrument that I have ever used." In the course of his work with Poulter, Van Allen learned machine shop practice, glass blowing, welding and brazing, vacuum techniques and, of greatest importance, the essential elements of original experimental research.〔 Poulter invited Van Allen to accompany him as a member of the Antarctic Expedition, but his parents vetoed the idea. He had to be content with listening avidly to the short-wave radio reports from Little America to follow the expedition’s progress. He, with the rest of the world, was electrified by Poulter’s heroic rescue of Admiral Byrd from his lonely vigil at South Pole Station in August 1934. Poulter and Byrd were honored by a public parade in Mount Pleasant the next summer, and Admiral Byrd delivered the chief commencement address at Van Allen’s graduation exercises. Van Allen went to his “family” university, the State University of Iowa, for his graduate work in physics. The physics faculty at the time numbered five, George W. Stewart (department head from 1909), John A. Eldridge, Edward P. T. Tyndall, Claude J. Lapp, and Alexander Ellett. Van Allen’s master’s thesis in solid-state physics, with Tyndall as his advisor, was entitled: ''A Sensitive Apparatus for Determining Young’s Modulus at Small Tensional Strains.'' He received his M.S. degree at the end of his first year there, in 1936. A fellowship allowed him to continue studying nuclear physics at the Carnegie Institution in Washington, D.C., where he also became immersed in research in geomagnetism, cosmic rays, auroral physics and the physics of Earth's upper atmosphere. For his Ph.D. research, he worked with Professor Ellett, who was switching his primary focus at that time from atomic beams to experimental nuclear physics. As part of his work, Van Allen, with Robert Huntoon and others, built a highly improvised Cockroft-Walton high-voltage power supply and accelerator. After much hard work and diligent coaxing of the cantankerous machine, he was eventually able to make a pair of successful runs, resulting in his dissertation: ''Absolute Cross-Section for the Nuclear Disintegration H2 + H2 > H3 + H1 and Its Dependence on Bombarding Energy (to 380 keV )''. He received his Ph.D. degree in June 1939. From 1940 through 1942, he helped develop radio proximity fuzes—detonators to increase the effectiveness of anti-aircraft fire—for the defense of ships. Sponsored by the National Defense Research Council, his work was conducted at the Carnegie Institution of Washington and at the Applied Physics Laboratory of Johns Hopkins University. In November 1942, he was commissioned as a naval officer, and he served 16 months on various ships in the South Pacific Fleet as assistant staff gunnery officer. In 1946, Van Allen returned to the Applied Physics Laboratory where he organized and directed a team to conduct high-altitude experimental work using V2 and Aerobee rockets, and, in 1951, he accepted a Guggenheim research fellowship at the Brookhaven National Laboratory. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「James Van Allen」の詳細全文を読む スポンサード リンク
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