Copyright © National Academy of Sciences. All rights reserved.
Solar and Space Physics: A Science for a Technological Society
86
SOLAR AND SPACE PHYSICS: A SCIENCE FOR A TECHNOLOGICAL SOCIETY
BOX 4.3 WHOLE HELIOSPHERE INTERVAL
The Whole Heliosphere Interval (WHI) was an international observing and modeling effort to characterize
the three-dimensional, interconnected, heliophysical system, utilizing dozens of space- and ground-based solar,
heliospheric, geospace, and upper-atmosphere observatories and instruments. WHI was the largest period of
focus of the International Heliophysical Year (IHY) (2007-2008), which was inspired by the 50th anniversary of
the International Geophysical Year (IGY) (in 1957-1958) and the subsequent 50 years of space exploration. The
goal of studying the structure and dynamics originating from one solar rotation (March 20-April 16, 2008) was
to describe a complete narrative from the Sun to Earth and beyond at solar minimum. A broad range of data
analysis and modeling was achieved, with multidisciplinary and international collaborations aided by a central
website (http://ihy2007.org/WHI) and WHI special sessions at international meetings. Many papers relating to
the WHI period have been published to date, including 27 that made up a 2011 topical issue of Solar Physics:
“The Sun–Earth Connection near Solar Minimum.” 1
1 M.M. Bisi, B.A. Emery, and B.J. Thompson, eds., “The Sun–Earth Connection near Solar Minimum,” Solar Physics, Volume 274, 2011.
BOX 4.4 LABORATORY EXPERIMENTS RELEVANT TO HELIOPHYSICS
Some important problems in solar and space physics will always be difficult to solve from spacecraft observations alone, where remote sensing introduces observational biases and in situ measurements are limited
to a small number of trajectories in a complex, time-variable environment. In contrast, dedicated laboratory
experiments offer the advantage of a controlled environment where detailed reproducible measurements are
possible.
An example of a problem on which laboratory experiments have had a significant science impact is magnetic reconnection. The transition between resistive magnetohydrodynamic and kinetic regimes is one of the
most fundamental issues in the study of magnetic reconnection. This transition has important implications
for the solar atmosphere and the magnetosphere, but it cannot be tested with direct satellite measurements
because plasmas in the magnetosphere and solar wind are nearly collisionless. Laboratory experiments over
the past decade have provided confirmation of the collisional-to-kinetic transition, allowing researchers to more
confidently predict the reconnection dynamics in various regions of the solar atmosphere and magnetosphere.
Although most laboratory experiments are directed toward understanding basic plasma physics issues,
there are also important experiments whose results are used directly to facilitate the interpretation of satellite
observations, e.g., spectroscopy measurements of molecules and highly charged ions and modeling of solar
wind interactions with airless bodies and dusty plasmas. The measurements of the cross sections associated
with ionization, charge exchange, and direct and dielectronic recombination are ongoing and provide key input
to the interpretation of satellite spectral measurements and the benchmarking of models.
particular the importance of collaborations between the NASA Heliophysics and Earth Science programs.
Similarly, the survey committee endorses collaborations across the Heliophysics, Astrophysics, and Planetary Sciences divisions.
Coordinated Observations
Data from diverse space- and ground-based instruments need to be routinely combined in order to
maximize their multiscale potential. In fact, such coordinated investigations are likely to be a crucial ele-
Solar and Space Physics: A Science for a Technological Society
86
SOLAR AND SPACE PHYSICS: A SCIENCE FOR A TECHNOLOGICAL SOCIETY
BOX 4.3 WHOLE HELIOSPHERE INTERVAL
The Whole Heliosphere Interval (WHI) was an international observing and modeling effort to characterize
the three-dimensional, interconnected, heliophysical system, utilizing dozens of space- and ground-based solar,
heliospheric, geospace, and upper-atmosphere observatories and instruments. WHI was the largest period of
focus of the International Heliophysical Year (IHY) (2007-2008), which was inspired by the 50th anniversary of
the International Geophysical Year (IGY) (in 1957-1958) and the subsequent 50 years of space exploration. The
goal of studying the structure and dynamics originating from one solar rotation (March 20-April 16, 2008) was
to describe a complete narrative from the Sun to Earth and beyond at solar minimum. A broad range of data
analysis and modeling was achieved, with multidisciplinary and international collaborations aided by a central
website (http://ihy2007.org/WHI) and WHI special sessions at international meetings. Many papers relating to
the WHI period have been published to date, including 27 that made up a 2011 topical issue of Solar Physics:
“The Sun–Earth Connection near Solar Minimum.” 1
1 M.M. Bisi, B.A. Emery, and B.J. Thompson, eds., “The Sun–Earth Connection near Solar Minimum,” Solar Physics, Volume 274, 2011.
BOX 4.4 LABORATORY EXPERIMENTS RELEVANT TO HELIOPHYSICS
Some important problems in solar and space physics will always be difficult to solve from spacecraft observations alone, where remote sensing introduces observational biases and in situ measurements are limited
to a small number of trajectories in a complex, time-variable environment. In contrast, dedicated laboratory
experiments offer the advantage of a controlled environment where detailed reproducible measurements are
possible.
An example of a problem on which laboratory experiments have had a significant science impact is magnetic reconnection. The transition between resistive magnetohydrodynamic and kinetic regimes is one of the
most fundamental issues in the study of magnetic reconnection. This transition has important implications
for the solar atmosphere and the magnetosphere, but it cannot be tested with direct satellite measurements
because plasmas in the magnetosphere and solar wind are nearly collisionless. Laboratory experiments over
the past decade have provided confirmation of the collisional-to-kinetic transition, allowing researchers to more
confidently predict the reconnection dynamics in various regions of the solar atmosphere and magnetosphere.
Although most laboratory experiments are directed toward understanding basic plasma physics issues,
there are also important experiments whose results are used directly to facilitate the interpretation of satellite
observations, e.g., spectroscopy measurements of molecules and highly charged ions and modeling of solar
wind interactions with airless bodies and dusty plasmas. The measurements of the cross sections associated
with ionization, charge exchange, and direct and dielectronic recombination are ongoing and provide key input
to the interpretation of satellite spectral measurements and the benchmarking of models.
particular the importance of collaborations between the NASA Heliophysics and Earth Science programs.
Similarly, the survey committee endorses collaborations across the Heliophysics, Astrophysics, and Planetary Sciences divisions.
Coordinated Observations
Data from diverse space- and ground-based instruments need to be routinely combined in order to
maximize their multiscale potential. In fact, such coordinated investigations are likely to be a crucial ele-