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Solar and Space Physics: A Science for a Technological Society
RECOMMENDATIONS
99
The mission would focus on making ENA maps and sampling local cosmic-ray particles concurrently
with in situ Voyager measurements of the heliospheric boundary region. IMAP enables the understanding
of particle acceleration through:
• Measurements of energetic (suprathermal) ions that originate from the solar wind, interstellar
medium, and inner heliosphere with unprecedented sensitivity and time resolution;
• Environmental monitoring of pickup ion 12 (PUI) distributions that is critical for effective background
evaluation and removal from ENA maps; and
• Comprehensive interplanetary particle and field monitoring in support of geospace interaction studies and space weather observations at the ideal location, L1.
IMAP Mission Concept
A notional spacecraft and instrument implementation for IMAP is based largely on ACE and IBEX.
IMAP is a Sun-pointed spinner, with spin axis readjustment every few days to provide all-sky maps every
6 months. The L1 placement avoids magnetospheric ENA backgrounds and enables continuous interplanetary observations. Mission goals are achieved with a 2-year baseline, including transit to L1, with possible
extension to longer operation (which would be particularly beneficial for long-term L1 monitoring). IMAP
combines the measurement capabilities shown in Table 4.3, all of which are feasible based on extrapolations of current instrument technologies.
IMAP Contribution to the Heliophysics Systems Observatory
Observations from many spacecraft in the HSO contribute dramatically to understanding solar energetic particle events, the importance of suprathermal ions for efficient further energization, the sources
and evolution of solar wind, solar-wind and energetic-particle inputs into geospace, and evolution of the
solar-heliospheric magnetic field. These observables are controlled by a myriad of complex and poorly
understood physical effects acting on distinct particle populations. IMAP combines highly sensitive PUI
and suprathermal-ion sensors to provide the critical species, spectral coverage, and temporal resolution
to address these physical processes. As an L1 monitor, IMAP also would fill a critical hole in Sun-Earth
system observations by measuring the solar wind input, knowledge of which is essential to studying magnetospheric and upper atmospheric processes.
DYNAMIC (Dynamical Neutral Atmosphere-Ionosphere Coupling)
DYNAMIC Overview
DYNAMIC is designed to answer the question: How does lower-atmosphere variability affect geospace?
To understand how lower-atmosphere variability drives neutral and plasma variability in the IT system, a
mission must address wave coupling with the lower atmosphere. The representative mission developed
and studied for this survey is designed to do two things. First, it will reveal the fundamental processes (e.g.,
wave dissipation, interactions between flow of different species) that underlie the transfer of energy and
momentum into the IT system (especially within the critical 100- to 200-km height regime). Second, it will
measure the resultant thermospheric and ionospheric variability that these waves incur at higher altitudes.
It will do these on a global scale, with high-inclination satellites launched into orbits separated by 6 hours
12 Pickup ions are formed when interstellar neutral atoms interact with the solar wind plasma and become ionized. The now charged
particles are carried (thus the origin of the term “pickup”) outward by the Sun’s magnetic field to the solar wind termination shock.
Solar and Space Physics: A Science for a Technological Society
RECOMMENDATIONS
99
The mission would focus on making ENA maps and sampling local cosmic-ray particles concurrently
with in situ Voyager measurements of the heliospheric boundary region. IMAP enables the understanding
of particle acceleration through:
• Measurements of energetic (suprathermal) ions that originate from the solar wind, interstellar
medium, and inner heliosphere with unprecedented sensitivity and time resolution;
• Environmental monitoring of pickup ion 12 (PUI) distributions that is critical for effective background
evaluation and removal from ENA maps; and
• Comprehensive interplanetary particle and field monitoring in support of geospace interaction studies and space weather observations at the ideal location, L1.
IMAP Mission Concept
A notional spacecraft and instrument implementation for IMAP is based largely on ACE and IBEX.
IMAP is a Sun-pointed spinner, with spin axis readjustment every few days to provide all-sky maps every
6 months. The L1 placement avoids magnetospheric ENA backgrounds and enables continuous interplanetary observations. Mission goals are achieved with a 2-year baseline, including transit to L1, with possible
extension to longer operation (which would be particularly beneficial for long-term L1 monitoring). IMAP
combines the measurement capabilities shown in Table 4.3, all of which are feasible based on extrapolations of current instrument technologies.
IMAP Contribution to the Heliophysics Systems Observatory
Observations from many spacecraft in the HSO contribute dramatically to understanding solar energetic particle events, the importance of suprathermal ions for efficient further energization, the sources
and evolution of solar wind, solar-wind and energetic-particle inputs into geospace, and evolution of the
solar-heliospheric magnetic field. These observables are controlled by a myriad of complex and poorly
understood physical effects acting on distinct particle populations. IMAP combines highly sensitive PUI
and suprathermal-ion sensors to provide the critical species, spectral coverage, and temporal resolution
to address these physical processes. As an L1 monitor, IMAP also would fill a critical hole in Sun-Earth
system observations by measuring the solar wind input, knowledge of which is essential to studying magnetospheric and upper atmospheric processes.
DYNAMIC (Dynamical Neutral Atmosphere-Ionosphere Coupling)
DYNAMIC Overview
DYNAMIC is designed to answer the question: How does lower-atmosphere variability affect geospace?
To understand how lower-atmosphere variability drives neutral and plasma variability in the IT system, a
mission must address wave coupling with the lower atmosphere. The representative mission developed
and studied for this survey is designed to do two things. First, it will reveal the fundamental processes (e.g.,
wave dissipation, interactions between flow of different species) that underlie the transfer of energy and
momentum into the IT system (especially within the critical 100- to 200-km height regime). Second, it will
measure the resultant thermospheric and ionospheric variability that these waves incur at higher altitudes.
It will do these on a global scale, with high-inclination satellites launched into orbits separated by 6 hours
12 Pickup ions are formed when interstellar neutral atoms interact with the solar wind plasma and become ionized. The now charged
particles are carried (thus the origin of the term “pickup”) outward by the Sun’s magnetic field to the solar wind termination shock.