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Solar and Space Physics: A Science for a Technological Society
REPORT OF THE PANEL ON SOLAR AND HELIOSPHERIC PHYSICS
303
• High-cadence suprathermal-ion observations. Overlapping with the PUI sensor, a suprathermal-ion
sensor provides composition (0.03-5 MeV/nuc) and charge state (0.03-1 MeV/e) for H through ultra-heavy
ions (1-min cadence for H and He).
• Solar wind and interplanetary monitoring suite. This suite mitigates backgrounds for high-sensitivity
ENA observations and provides societally important real-time solar wind and cosmic-ray monitoring. It
measures solar wind ions (0.1-20 keV/e) and electrons (0.005-2 keV) every 15 s, the magnetic field at 16
Hz, and SEP, anomalous cosmic-ray, and galactic cosmic-ray electrons and ions (H-Fe) over 2- to 200-MeV/
nuc.
10.5.2.3 Solar-C
Solar-C is a Japan-led mission expected to include substantial contributions from the United States and
Europe. 13 It builds on the highly successful Yohkoh and Hinode collaborations with the United States’ most
reliable partner. As with Yohkoh and Hinode, Japan will provide the satellite and launch. Almost all NASA
funding would go to the U.S. science community for state-of-the-art instrumentation and data analysis.
Hence, Solar-C presents an important opportunity to leverage NASA science funding.
The science objectives of Solar-C are to determine:
• How the energy that sustains the Sun’s atmosphere is created on small scales and transported into
the large-scale corona and solar wind;
• How magnetic energy is dissipated in astrophysical plasmas; and
• How small-scale physical processes initiate large-scale dynamic phenomena, such as CMEs and
flares, which drive space weather.
Achieving those objectives is a prerequisite for meeting SHP panel science goals 2 and 3. Solar-C is
central to the science strategy for the next decade; therefore, the panel strongly endorses U.S. participation
in the mission. As with Hinode, the data should be open to the full U.S. science community. Furthermore,
a competitive Solar-C guest-investigator program, overseen by NASA, that follows the guidelines of the
general guest-investigator program initiative would achieve maximum science benefit (§10.5.3.4).
To meet its three objectives, Solar-C will obtain highly precise spectroscopic and polarimetric measurements designed to determine the full-vector magnetic field accurately, especially in the chromosphere,
and high-throughput measurements designed to resolve the plasma dynamics. Furthermore, spectroscopic
measurements that seamlessly cover each temperature domain of the solar atmosphere—the photosphere,
lower chromosphere, upper chromosphere, transition region, inner corona, and high-temperature flare—
will be obtained to improve understanding of the entire chain of energy transport and dissipation. Finally,
high-spatial-resolution measurements will be obtained for resolving elementary physical processes.
Solar-C can meet its measurement strategy with three strawman instruments designed to deliver an
order-of-magnitude improvement over present measurement capabilities:
• A Solar UV-visible-IR telescope that will resolve and measure magnetic fields and gas dynamics in
the lower atmosphere—from the photosphere through the upper chromosphere—with a diffraction-limited
telescope that has an aperture 1.5 m in diameter.
• An EUV/FUV high-throughput spectrometer that will measure spectral lines in the FUV-EUV region
from plasma in the upper chromosphere, transition region, lower corona, and flares simultaneously to
13 G. Doschek et al., The High-Resolution Solar-C International Collaboration: Probing the Coupled Dynamics of the Solar Atmosphere, white paper submitted to the Decadal Strategy for Solar and Space Physics (Heliophysics), Paper 60.
Solar and Space Physics: A Science for a Technological Society
REPORT OF THE PANEL ON SOLAR AND HELIOSPHERIC PHYSICS
303
• High-cadence suprathermal-ion observations. Overlapping with the PUI sensor, a suprathermal-ion
sensor provides composition (0.03-5 MeV/nuc) and charge state (0.03-1 MeV/e) for H through ultra-heavy
ions (1-min cadence for H and He).
• Solar wind and interplanetary monitoring suite. This suite mitigates backgrounds for high-sensitivity
ENA observations and provides societally important real-time solar wind and cosmic-ray monitoring. It
measures solar wind ions (0.1-20 keV/e) and electrons (0.005-2 keV) every 15 s, the magnetic field at 16
Hz, and SEP, anomalous cosmic-ray, and galactic cosmic-ray electrons and ions (H-Fe) over 2- to 200-MeV/
nuc.
10.5.2.3 Solar-C
Solar-C is a Japan-led mission expected to include substantial contributions from the United States and
Europe. 13 It builds on the highly successful Yohkoh and Hinode collaborations with the United States’ most
reliable partner. As with Yohkoh and Hinode, Japan will provide the satellite and launch. Almost all NASA
funding would go to the U.S. science community for state-of-the-art instrumentation and data analysis.
Hence, Solar-C presents an important opportunity to leverage NASA science funding.
The science objectives of Solar-C are to determine:
• How the energy that sustains the Sun’s atmosphere is created on small scales and transported into
the large-scale corona and solar wind;
• How magnetic energy is dissipated in astrophysical plasmas; and
• How small-scale physical processes initiate large-scale dynamic phenomena, such as CMEs and
flares, which drive space weather.
Achieving those objectives is a prerequisite for meeting SHP panel science goals 2 and 3. Solar-C is
central to the science strategy for the next decade; therefore, the panel strongly endorses U.S. participation
in the mission. As with Hinode, the data should be open to the full U.S. science community. Furthermore,
a competitive Solar-C guest-investigator program, overseen by NASA, that follows the guidelines of the
general guest-investigator program initiative would achieve maximum science benefit (§10.5.3.4).
To meet its three objectives, Solar-C will obtain highly precise spectroscopic and polarimetric measurements designed to determine the full-vector magnetic field accurately, especially in the chromosphere,
and high-throughput measurements designed to resolve the plasma dynamics. Furthermore, spectroscopic
measurements that seamlessly cover each temperature domain of the solar atmosphere—the photosphere,
lower chromosphere, upper chromosphere, transition region, inner corona, and high-temperature flare—
will be obtained to improve understanding of the entire chain of energy transport and dissipation. Finally,
high-spatial-resolution measurements will be obtained for resolving elementary physical processes.
Solar-C can meet its measurement strategy with three strawman instruments designed to deliver an
order-of-magnitude improvement over present measurement capabilities:
• A Solar UV-visible-IR telescope that will resolve and measure magnetic fields and gas dynamics in
the lower atmosphere—from the photosphere through the upper chromosphere—with a diffraction-limited
telescope that has an aperture 1.5 m in diameter.
• An EUV/FUV high-throughput spectrometer that will measure spectral lines in the FUV-EUV region
from plasma in the upper chromosphere, transition region, lower corona, and flares simultaneously to
13 G. Doschek et al., The High-Resolution Solar-C International Collaboration: Probing the Coupled Dynamics of the Solar Atmosphere, white paper submitted to the Decadal Strategy for Solar and Space Physics (Heliophysics), Paper 60.