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A Science Strategy for Space Physics: Part II A Science Strategy for Space Physics Part II The Key Topics in Space Physics Research Part II of this report discusses five key topics that the committees believe must be addressed by the space physics community in the coming decade. No attempt has been made to prioritize the topics themselves; they are all important. The CSSP and CSTR do, however, prioritize the approaches to trying to answer each topic's major questions. Although the report covers what the committees consider should be the major emphases in the field, there must also be a broad spectrum of other types of research, most of which could be classified as "small science," that may in turn lead to the major thrusts for the following decade. Several aspects of each of the key topics are considered, including: The importance of the topic; REPORT MENU NOTICE MEMBERSHIP The current state of knowledge; SUMMARY PART I The principal outstanding questions or unproved theories; PART II CHAPTER 1 CHAPTER 2 The extent to which the currently approved programs are expected to CHAPTER 3 address the outstanding questions. This assessment is based on the optimistic CHAPTER 4 assumption that the entire currently approved program will be successfully CHAPTER 5 completed-that those NASA space missions that have been approved for a new PART III start will be launched and will operate successfully and that current NSF APPENDIX initiatives will be funded to successful completion; and The efforts required beyond the currently approved program, with focus on the next decade. Although the current program can be expected to acquire the new data or insights it was designed to obtain, it will also lead to a new set of questions that had not been foreseen. Those new questions are necessarily beyond the scope of the present study. It is, however, possible to recognize the known limitations of, or gaps in, the currently approved program file:///C|/SSB_old_web/strapart2.html (1 of 3) [6/18/2004 2:18:35 PM]

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A Science Strategy for Space Physics: Part II and to sketch out what needs to be done next. It is obvious that any science strategy must be frequently reviewed and updated to take account of recent events. In describing the recommended future directions, the CSSP and CSTR have considered what needs to be measured, to what accuracy, and, in some cases, with what new or emerging technology. The committees do not, however, address implementation issues such as whether something is best done with a small Explorer or a large mission, nor the temporal sequence of new space missions. Such plans are the responsibility of the implementing agencies and are more subject to the political process than is the establishment of scientific objectives, which are the focus of this report. Before each of the key topics is discussed, an overarching statement is required about the role of theory and numerical simulation. The importance of theoretical research in space physics has been emphasized repeatedly in NRC studies.1 This type of research must not be separated from the observational programs. It must continue to be a central element associated with every single one of the five key topics, in both the immediate and the more distant future. Theory is what connects the measurements to scientific understanding. The committees encourage and expect to see an evolution in the level of sophistication of theory and numerical simulations. The growing availability of supercomputers and massively parallel computers will allow the development of increasingly realistic magnetohydrodynamic models extended to three dimensions. For many problems, it is necessary to go beyond quasilinear theory and come to grips with strongly nonlinear effects; new methods and even new languages are being developed to treat those nonlinearities. The presentation of the key topics arbitrarily starts at the center of the Sun, progresses through the solar atmosphere and solar wind to the Earth's magnetosphere and atmosphere, and then concludes with the cosmic rays entering the solar system from the galaxy and the universe. NOTE 1. See, for example, Board on Atmospheric Sciences and Climate and the Space Studies Board, National Research Council, A Space Physics Paradox: Why Has Increased Funding Been Accompanied by Decreased Effectiveness in the Conduct of Space Physics Research?, National Academy Press, Washington, D.C., 1994; and Space Studies Board, National Research Council, Assessment of Programs in Solar and Space Physics-1991, National Academy Press, Washington, D.C., 1991. file:///C|/SSB_old_web/strapart2.html (2 of 3) [6/18/2004 2:18:35 PM]