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Introduction
A solar maximum is a cosmic “event” in the same sense as the periodic return of a comet or the episodic burst from an exotic astrophysical source. Records of various kinds indicate that the Sun has repeated its version of celestial fireworks in the form of flares, radio bursts, and coronal eruptions on a roughly 11-year cycle throughout geologic and human history. The predictability of a solar maximum's occurrence is a great boon to scientists because it allows advanced preparation for detailed study of primary astrophysical processes as well as their interplanetary and planetary consequences. During a solar maximum, processes generating energetic particles and photons can be observed on a large scale, and scientists can extrapolate these observations to try to characterize the physical processes in less easily investigated regions of the cosmos, in particular, the neighborhoods of other stars. Changes in solar activity also have direct relevance to humans. The increased emissions of solar particles and radiation and the enhanced interplanetary magnetic fields associated with a solar maximum cause measurable changes on Earth and in its space environment. A solar maximum thus allows the analysis of the response of Earth's atmosphere and climate to extreme and variable solar conditions of the kind believed to have prevailed early in the solar system's history. The solar maximum period is thus highly pertinent to the search for life's origins, a quest that recently has captured the public's and NASA's attention.
Solar activity also has technological impacts. Historically, the solar maximum has been the time when problems related to short-term variations in the Sun's radiative and particle outputs occur most frequently. As our nation increases its investment in commercial space applications, we become more vulnerable to these effects. For example, the increased use of space-based communication and navigation systems and the scheduled construction of the International Space Station (in an orbit subject to hazards arising from solar events and their effects) bring a greater urgency to the need to understand how the active Sun affects geospace, or “space weather.” Before anyone can embark on long-term crewed flight beyond the protection of Earth's magnetosphere (such as manned exploration of the Moon or Mars), the likely extent and effects of solar variability must be known. The coming solar maximum offers an unprecedented opportunity to make significant advances in this challenging endeavor.
In this short report, the Committee on Solar and Space Physics (CSSP) and the Committee on Solar-Terrestrial Research (CSTR) assess the extent to which the United States is prepared to take advantage of the approaching solar maximum, expected to occur between 1999 and 2002. This readiness consists of preparation to take advantage of research opportunities unique to the solar maximum, and a capability for mitigating problems that might result from the effects of the active Sun. The committees' assessment consists primarily of a review of the relevant activities of the agencies most concerned with the use or investigation of space: the National Aeronautics and Space Administration (NASA), the nation's “space agency” responsible for solar and geospace exploration as well as the human use of space; the National Oceanic and Atmospheric Administration (NOAA), the major provider of civilian solar and space environment information; the National Science Foundation (NSF), a major sponsor of basic solar-terrestrial research and the lead agency for the National Space Weather Program
(NSWP);1 the Department of Defense (DOD), in particular the Air Force, which has its own space environment monitoring and research program in support of DOD, and the Navy, which historically has been a major participant in solar and ionospheric research; and the Department of Energy (DOE), whose support of space activities related to defense and other national security needs includes a group at Los Alamos National Laboratory that analyzes aspects of the the space environment that affect national security.
The report begins with a brief description of the considerations that led to this assessment, followed by summaries of each agency 's activities and programs, including any special plans adopted in anticipation of the solar maximum. These descriptions were drawn in part from information obtained during agency briefings for the CSSP/CSTR at their February 26-28, 1997, meeting in Washington, D.C. It then offers an assessment of these various programs regarding their optimal use of national resources to both learn from and protect against the events of the rapidly approaching solar maximum. It concludes with recommendations regarding important additional benefits that could be derived, in many cases with existing resources or minimal additional investment.
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The committees' review of agency activities does not include an assessment of the current capabilities and future options for ground-based optical and radio solar observatories. In particular, the present report does not make recommendations related to the NSF-funded National Solar Observatory at Sacramento Peak, New Mexico, and Kitt Peak, Arizona. Such an assessment is being performed as part of an ongoing National Research Council study by the Space Studies Board's Task Group on Ground-based Solar Research (TGGSR). |