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Solar and Space Physics: A Science for a Technological Society
261
10
Report of the Panel on Solar
and Heliospheric Physics
To grasp immediately the nature of the field of solar and heliospheric physics, one need only look at
the striking image of the 2010 solar eclipse shown in Figure 10.1. The solar atmosphere extends outward
from the Sun’s surface, apparently without end. In fact, this extended atmosphere—the heliosphere—does
end at roughly 140 AU, where the solar wind runs into the galaxy at the heliopause. Our Earth, its upper
atmosphere, and its magnetosphere—and the other planets of the solar system—are all embedded deep
inside this extended stellar atmosphere. Hence, the vast physical domain stretching from the center of the
Sun out to the heliopause defines our home in space. The heliopause is where our home ends and the
rest of the universe begins.
10.1 PHYSICS OF THE SUN AND HELIOSPHERE—MAJOR SCIENCE GOALS
To achieve the key science goals set forth by this decadal survey in Chapter 1, it is necessary to
understand the physical processes that create and sustain connections within the heliosphere. Figure 10.1
demonstrates, however, that gaining such an understanding requires overcoming major fundamental physics
challenges. The most striking feature of the image is its beautifully intricate structure—obviously due to the
Sun’s magnetic field—that has its origins deep below the solar surface. Understanding the processes that
produce the solar field is a prerequisite for achieving the goals of the survey, but the recent, unexpected
deep solar minimum demonstrates that understanding of the Sun’s dynamo is still rudimentary. Consequently, the Panel on Solar and Heliospheric Physics (SHP) identified as the first of four SHP science goals
for the upcoming decade, SHP1, to determine how the Sun generates the quasi-cyclical variable magnetic
field that extends throughout the heliosphere.
The extended structure of Figure 10.1 shows that the magnetic field provides a coupling across the
solar and heliospheric domain, from the solar interior to the galaxy. In fact, the field not only couples
the solar and heliospheric domain but also is essential for its creation. All current theories for heating the
corona and accelerating the wind postulate the magnetic field as the central agent. Although this is not
immediately obvious from Figure 10.1, because it is only a snapshot, the magnetic coupling of the Sun
and heliosphere is always dynamic. The field at the solar surface and low corona is observed to vary dra-
Solar and Space Physics: A Science for a Technological Society
261
10
Report of the Panel on Solar
and Heliospheric Physics
To grasp immediately the nature of the field of solar and heliospheric physics, one need only look at
the striking image of the 2010 solar eclipse shown in Figure 10.1. The solar atmosphere extends outward
from the Sun’s surface, apparently without end. In fact, this extended atmosphere—the heliosphere—does
end at roughly 140 AU, where the solar wind runs into the galaxy at the heliopause. Our Earth, its upper
atmosphere, and its magnetosphere—and the other planets of the solar system—are all embedded deep
inside this extended stellar atmosphere. Hence, the vast physical domain stretching from the center of the
Sun out to the heliopause defines our home in space. The heliopause is where our home ends and the
rest of the universe begins.
10.1 PHYSICS OF THE SUN AND HELIOSPHERE—MAJOR SCIENCE GOALS
To achieve the key science goals set forth by this decadal survey in Chapter 1, it is necessary to
understand the physical processes that create and sustain connections within the heliosphere. Figure 10.1
demonstrates, however, that gaining such an understanding requires overcoming major fundamental physics
challenges. The most striking feature of the image is its beautifully intricate structure—obviously due to the
Sun’s magnetic field—that has its origins deep below the solar surface. Understanding the processes that
produce the solar field is a prerequisite for achieving the goals of the survey, but the recent, unexpected
deep solar minimum demonstrates that understanding of the Sun’s dynamo is still rudimentary. Consequently, the Panel on Solar and Heliospheric Physics (SHP) identified as the first of four SHP science goals
for the upcoming decade, SHP1, to determine how the Sun generates the quasi-cyclical variable magnetic
field that extends throughout the heliosphere.
The extended structure of Figure 10.1 shows that the magnetic field provides a coupling across the
solar and heliospheric domain, from the solar interior to the galaxy. In fact, the field not only couples
the solar and heliospheric domain but also is essential for its creation. All current theories for heating the
corona and accelerating the wind postulate the magnetic field as the central agent. Although this is not
immediately obvious from Figure 10.1, because it is only a snapshot, the magnetic coupling of the Sun
and heliosphere is always dynamic. The field at the solar surface and low corona is observed to vary dra-