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Solar and Space Physics: A Science for a Technological Society
304
SOLAR AND SPACE PHYSICS: A SCIENCE FOR A TECHNOLOGICAL SOCIETY
trace energy flow throughout the solar atmosphere and follow the energy released by such processes as
magnetic reconnection and instabilities.
• An X-ray imaging (spectroscopic) telescope that will resolve and measure the plasma in the hot
corona to improve our understanding of its elemental structure, origins, and dynamics.
The strawman instruments outlined above are only for the purposes of planning and costing the mission. Concrete plans for the instruments and for the roles of the international partners are urgently needed;
consequently, it is a high priority of the SHP panel that, as with Hinode, NASA and its partners form a
Science and Technology Definition Team for Solar-C as soon as possible. Although the NASA contribution
has yet to be decided, the panel expects that NASA contributions would involve the most technically challenging elements, such as the focal-plane packages (cameras, detectors, and so on), which would afford
the U.S. science community an opportunity to make critical advances in remote-sensing capabilities. The
total cost to NASA through Phase E should be capped at $250 million.
Solar-C presents a unique opportunity for solar and space physics to make flagship-level science
advances for the cost of an Explorer.
10.5.2.4 Solar Eruptive Events Mission
Major solar eruptive events, consisting of both large flares and fast massive CMEs, are the most powerful explosions and particle accelerators in the solar system (Figure 10.22). They produce the most extreme
space weather, generating SEPs that pose a major radiation hazard for spacecraft and humans, intense
photon emissions that disrupt GPS and communications (see Figure 10.13), and storms in the magnetosphere that can cause power blackouts and disable satellites. Thus, understanding the fundamental physics
of solar eruptive events is one of the most important goals of heliophysics.
Observations indicate that the flare energy-release particle-acceleration region is high above the flare
X-ray loops (§10.3.3). The acceleration of fast CMEs is synchronized with the flare energy release, and
this suggests that magnetic reconnection in the current sheet behind the CME both generates the flare and
accelerates the CME. The CME-driven shock then accelerates SEPs. Despite much progress in developing
this picture, fundamental physics questions remain:
• How is magnetic energy suddenly released to produce both a flare and a CME?
• How are CMEs accelerated to high speeds?
• How can flares accelerate electrons and ions so efficiently?
• How are escaping SEPs accelerated to such high energies?
• How can the magnetic energy for major solar eruptive events be accumulated in the corona?
To make major breakthroughs, a single-spacecraft SEE 14 mission in low Earth orbit, with powerful new
instruments and a roughly 10-m boom for optics and occulter (Figure 10.23), will provide, for the first time,
the following detailed measurements of accelerated electrons and ions plus ambient plasma conditions in
the energy-release particle-acceleration regions (SHP action 3a):
• Focusing Optics X-ray Spectroscopic Imager (FOXSI). Provides HXR (about 2 to over about 80 keV)
imaging (about 7 arcsec) spectroscopy (less than about 1-keV full-width half-maximum [FWHM]) of accelerated electrons and hot thermal plasmas in the high-coronal-energy-release particle-acceleration region
14 R.P. Lin et al., Solar Eruptive Events (SEE) 2020 Mission Concept, white paper submitted to the Decadal Strategy for Solar and
Space Physics (Heliophysics), Paper 162.
Solar and Space Physics: A Science for a Technological Society
304
SOLAR AND SPACE PHYSICS: A SCIENCE FOR A TECHNOLOGICAL SOCIETY
trace energy flow throughout the solar atmosphere and follow the energy released by such processes as
magnetic reconnection and instabilities.
• An X-ray imaging (spectroscopic) telescope that will resolve and measure the plasma in the hot
corona to improve our understanding of its elemental structure, origins, and dynamics.
The strawman instruments outlined above are only for the purposes of planning and costing the mission. Concrete plans for the instruments and for the roles of the international partners are urgently needed;
consequently, it is a high priority of the SHP panel that, as with Hinode, NASA and its partners form a
Science and Technology Definition Team for Solar-C as soon as possible. Although the NASA contribution
has yet to be decided, the panel expects that NASA contributions would involve the most technically challenging elements, such as the focal-plane packages (cameras, detectors, and so on), which would afford
the U.S. science community an opportunity to make critical advances in remote-sensing capabilities. The
total cost to NASA through Phase E should be capped at $250 million.
Solar-C presents a unique opportunity for solar and space physics to make flagship-level science
advances for the cost of an Explorer.
10.5.2.4 Solar Eruptive Events Mission
Major solar eruptive events, consisting of both large flares and fast massive CMEs, are the most powerful explosions and particle accelerators in the solar system (Figure 10.22). They produce the most extreme
space weather, generating SEPs that pose a major radiation hazard for spacecraft and humans, intense
photon emissions that disrupt GPS and communications (see Figure 10.13), and storms in the magnetosphere that can cause power blackouts and disable satellites. Thus, understanding the fundamental physics
of solar eruptive events is one of the most important goals of heliophysics.
Observations indicate that the flare energy-release particle-acceleration region is high above the flare
X-ray loops (§10.3.3). The acceleration of fast CMEs is synchronized with the flare energy release, and
this suggests that magnetic reconnection in the current sheet behind the CME both generates the flare and
accelerates the CME. The CME-driven shock then accelerates SEPs. Despite much progress in developing
this picture, fundamental physics questions remain:
• How is magnetic energy suddenly released to produce both a flare and a CME?
• How are CMEs accelerated to high speeds?
• How can flares accelerate electrons and ions so efficiently?
• How are escaping SEPs accelerated to such high energies?
• How can the magnetic energy for major solar eruptive events be accumulated in the corona?
To make major breakthroughs, a single-spacecraft SEE 14 mission in low Earth orbit, with powerful new
instruments and a roughly 10-m boom for optics and occulter (Figure 10.23), will provide, for the first time,
the following detailed measurements of accelerated electrons and ions plus ambient plasma conditions in
the energy-release particle-acceleration regions (SHP action 3a):
• Focusing Optics X-ray Spectroscopic Imager (FOXSI). Provides HXR (about 2 to over about 80 keV)
imaging (about 7 arcsec) spectroscopy (less than about 1-keV full-width half-maximum [FWHM]) of accelerated electrons and hot thermal plasmas in the high-coronal-energy-release particle-acceleration region
14 R.P. Lin et al., Solar Eruptive Events (SEE) 2020 Mission Concept, white paper submitted to the Decadal Strategy for Solar and
Space Physics (Heliophysics), Paper 162.