the implementation of the program recommended in the 2003 solar and space physics decadal survey.1 Listed below are some of the highlights from an exciting decade of discovery:
• New insights, gained from novel observations and advances in theory, modeling, and computation, into the variability of the mechanisms that generate the Sun’s magnetic field, and into the structure of that field;
• A new understanding of the unexpectedly deep minimum in solar activity;
• Significant progress in understanding the origin and evolution of the solar wind;
• Striking advances in understanding both explosive solar flares and the coronal mass ejections that drive space weather;
• Groundbreaking discoveries about the surprising nature of the boundary between the heliosphere—the immense magnetic bubble containing our solar system—and the surrounding interstellar medium;
• New imaging methods that permit researchers to directly observe space weather-driven changes in the particles and magnetic fields surrounding Earth;
• Significantly deeper knowledge of the numerous processes involved in the acceleration and loss of particles in Earth’s radiation belts;
• Major advances in understanding the structure, dynamics, and linkages in other planetary magnetospheres, especially those of Mercury, Jupiter, and Saturn;
• New understanding of how oxygen from Earth’s own atmosphere contributes to space storms;
• The surprising discovery that conditions in near-Earth space are linked strongly to the terrestrial weather and climate below;
• Evidence of a long-term decline in the density of Earth’s upper atmosphere, indicative of planetary change; and
• New understanding of the temporal and spatial scales involved in magnetospheric-atmospheric coupling in Earth’s aurora.
It is noteworthy that some of the most surprising discoveries of the past decade have come from comparatively small missions that were tightly cost-constrained, competitively selected, and principal-investigator (PI)-led—recommendations in the present decadal survey reflect this insight.
Enabled by advances in scientific understanding as well as fruitful interagency partnerships, the capabilities of models that predict space weather impacts on Earth have also made rapid gains over the past decade. Reflecting these advances and a society increasingly vulnerable to the adverse effects of space weather, the number of users of space weather services has also grown rapidly. Indeed, a growing community has come to depend on constant and immediate access to space weather information (see Chapter 7).
KEY SCIENCE GOALS FOR THE NEXT DECADE
The significant achievements of the past decade have set the stage for transformative advances in solar and space physics for the coming decade. Reports from the survey’s three interdisciplinary study panels (Chapters 8-10) enumerate the highest-priority scientific opportunities and challenges for the com-
1 National Research Council, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics, The National Academies Press, Washington, D.C., 2003; and National Research Council, The Sun to the Earth—and Beyond: Panel Reports, The National Academies Press, Washington, D.C., 2003.