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THE NATIONAL ACADEMIES . ~ Advisers lo the Nation on Science, Engineering, and Medirine February 5, 2004 Dr. Hugh Van Horn Program Director Division of Materials Research National Science Foundation 4201 Wilson Boulevard Arlington, Virginia 22230 Dear Dr. Van Horn: ~ write as chair of the National Research Council's Committee on Opportunities in High Magnetic Field Science (COHMAG) to report on the progress of the committee's cleliberations to ciate. COHMAG has met twice: once in Washington, D.C., in September 2003 and again in Tallahassee, Florida, in December 2003. (Membership of the committee ant! agendas for these meetings are appended to this letter.) A final meeting is anticipated this coming spring, and the committee's report should be completed a few months after that. The charge to which COHMAG's full report will respond has four components: (~) to assess the current state and future prospects of high magnetic fielc! science ant] technology in the United States, (2) to assess the position of the United States in this area in the international context, (3) to identify promising multidisciplinary areas for research and development, en c! (4) to review ant! prioritize major magnet construction initiatives for the next decade. Although it has not yet completer! the discussions that will result in the development of its final conclusions and recommendations, the committee does have a sense of the current status of the area of high magnetic field science, and it has identified most of the major issues. It is important to understand from the outset how difficult it is to built! magnets significantly more powerful than those operating today. Since the National High Magnetic Field Laboratory was establisher! in Tallahassee about a decade ago, the field strengths of the most powerful direct current magnets available have increaser! by about 50 percent, but only at great expense and with great effort. There are a host of technical challenges. The stresses in high- field magnets test the strengths of the materials of which they are built. If the magnet is resistive, management of the heat it generates is a major problem, as are the ongoing cost of the power it consumes ant! the capital cost of the power supply neeciect to energize it. If the magnet is superconducting, the sensitivity of the resistance of the superconductor it contains to temperature ant! magnetic field! strength limits performance, ant! management of the energy stored in the magnet's field is crucial because accidental quenching is an ever-present possibility. In short, high-field magnet development is a very challenging area at the intersection of science and engineering, en c! in the future, increases in field strength as small as 10 percent will be hard won. Measured by the potential for constructing magnets that deliver even higher fields, the opportunities available in this area of science ant! technology are modest, but as the committee will endeavor to make clear in its final report, they are worth fighting for, especially because improvements in superconducting magnet technology could make high-field magnets more BOARD ON PHYSICS AND ASTRONOMY . Tel 202-334-3520 . Fax 202-334-3575 . E-mail bPa@naS.edU N~104t AcADEMY oF wIEN,(~$ ~ NMIoNAt AcADEMY oF ENGINEERING ~ IN~E ~ MEnIcINE ~ NMIoNAt kEsEARcH c - ~~t

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available for use. The committee invites! speakers to its first two meetings to brief its members on relevant fields of science and technology, including magnet technology and instrumentation, nuclear magnetic resonance in all its manifestations, semiconductors ant! heterostructures, high- temperature superconductors, ion cyclotron resonance, Tow-dimensional electron systems, magnetic resonance imaging, and the use of magnets in high energy physics ant! fusion science. The U.S. position is strong in most areas of science that depenc] on access to high magnetic f~elcIs but is not necessarily worIcI-leading across the board. The committee is investigating further to flesh out the details, but it is convincer! that it is important that the Uniter! States maintain facilities where cutting-edge research in magnet technology is carrier! out, and that the products of this research be made available to the wider community of scientists and engineers: There is a great deal of important, exciting science that can be done only at facilities of this kincI. In addition, advances both in magnet design and in our fundamental unclerstanding of magnetism are certain to have beneficial impacts on a host of technologies critical to the national welfare as well as on the many areas of science that use magnet-basec! technologies. The committee is still formulating its recommendations about how best to invest national resources in this area. Many additional questions are currently uncier discussion in the committee. For example, what can be clone to make high-field magnets more available for use at national neutron sources and synchrotron light sources? What can be clone to expand the access of scientists and engineers to high magnetic fields for research purposes more generally, and to increase the size of that user community? What research in magnet technology wouict do the most to advance the many fields of science that use magnetic fields? How should publicly sponsored research in magnet clevelopment be organized, given the existence of large efforts in the private sector that are driven by the market for MRT instruments and NMR spectrometers, both of which use superconducting magnets? ~ trust this {ester is sufficient to give you a sense of where COHMAG's cleliberations are taking it, and ~ look forward to transmitting a full report to you in the second half of 2004. Sincerely yours, /s/ Peter Moore, Chair Committee on Opportunities in High Magnetic Field Science 2