Copyright © National Academy of Sciences. All rights reserved.
Solar and Space Physics: A Science for a Technological Society
REPORT OF THE PANEL ON SOLAR WIND-MAGNETOSPHERE INTERACTIONS
215
• Motivation 1. Understand our home in the solar system. The fundamental motivation of wanting to
understand the fascinating Sun-Earth system drives the desire to learn what determines the dynamically
changing charged-particle environment of the magnetosphere, from the lowest-energy particles emerging
from the upper atmosphere, to the hazardous high-energy particles of the radiation belts. What exactly
are the relationships between the different magnetospheric regions, and how are these regions coupled to
the solar wind and upper atmosphere? How do these linkages determine magnetospheric dynamics? And
what new insights do researchers gain from examining the similarities and differences in these regions and
processes at other planets?
• Motivation 2. Predict the changing space environment and its societal impacts. A thorough understanding of this complex and highly coupled system will make it possible to predict its behavior under
a variety of changing conditions, allowing anticipation and recognition of conditions that are adverse to
human life and technology. Within the magnetosphere, researchers are particularly interested in how they
can evaluate and predict damaging particle populations and electrodynamic fields.
• Motivation 3. Reveal universal physical processes. The geospace system constitutes a laboratory
for exploring a wide variety of processes that operate throughout the universe. These include the ways
in which ionized outflows can be driven from planetary atmospheres; how waves and particles provide
coupling between disparate plasma regions; how plasmas interact with neutral materials; how magnetic
reconnection occurs and how it energizes particles; how collisionless shock waves work; and how plasma
turbulence is generated and dissipated and affects other dynamical processes.
The following sections outline recent progress made toward addressing the fundamental questions
raised by these motivations; indicate the outstanding problems where significant progress can be accomplished in the near future, leading to the identification of specific science goals for the coming decade;
and lay out the SWMI panel’s imperatives for actions that are needed to meet those goals.
9.3 SIGNIFICANT ACCOMPLISHMENTS OF THE PREVIOUS DECADE
9.3.1 Scientific Progression
The science of solar wind-magnetosphere interactions was established near the dawn of the space age,
only 50 years ago. Since that time, knowledge of the magnetosphere has grown tremendously, progressing
from discovery to understanding.
Early research focused on the discovery and exploration of the different regions that lie above Earth’s
atmosphere: the radiation belts, the plasmasphere, the plasma sheet, and the solar wind. As researchers
discovered these regions and the particle populations that define them, they sought to identify and understand the physical processes that accelerate and transport the particles. They also learned that the system
is not static, but rather exhibits substantial variability with identifiable patterns. It became clear that different regions are not independent, but rather are intimately linked, and the variability and processes in one
region can be clearly related to those in other regions.
Scientists now appreciate that the magnetosphere is a vast, highly coupled system that involves a
wide array of fundamental physical processes and complex linkages between different regions. In the past
decade this system’s impact on human technology and society has also come to be appreciated: storms
and other disturbances in geospace have significantly disrupted and disabled spacecraft and ground-based
power grids. Finally, as mankind has reached out to explore the solar system, researchers have discovered
that other solar system bodies possess magnetospheres that exhibit many of the same processes found near
Earth, but frequently manifested in different ways, and producing very different structure and dynamics.
Solar and Space Physics: A Science for a Technological Society
REPORT OF THE PANEL ON SOLAR WIND-MAGNETOSPHERE INTERACTIONS
215
• Motivation 1. Understand our home in the solar system. The fundamental motivation of wanting to
understand the fascinating Sun-Earth system drives the desire to learn what determines the dynamically
changing charged-particle environment of the magnetosphere, from the lowest-energy particles emerging
from the upper atmosphere, to the hazardous high-energy particles of the radiation belts. What exactly
are the relationships between the different magnetospheric regions, and how are these regions coupled to
the solar wind and upper atmosphere? How do these linkages determine magnetospheric dynamics? And
what new insights do researchers gain from examining the similarities and differences in these regions and
processes at other planets?
• Motivation 2. Predict the changing space environment and its societal impacts. A thorough understanding of this complex and highly coupled system will make it possible to predict its behavior under
a variety of changing conditions, allowing anticipation and recognition of conditions that are adverse to
human life and technology. Within the magnetosphere, researchers are particularly interested in how they
can evaluate and predict damaging particle populations and electrodynamic fields.
• Motivation 3. Reveal universal physical processes. The geospace system constitutes a laboratory
for exploring a wide variety of processes that operate throughout the universe. These include the ways
in which ionized outflows can be driven from planetary atmospheres; how waves and particles provide
coupling between disparate plasma regions; how plasmas interact with neutral materials; how magnetic
reconnection occurs and how it energizes particles; how collisionless shock waves work; and how plasma
turbulence is generated and dissipated and affects other dynamical processes.
The following sections outline recent progress made toward addressing the fundamental questions
raised by these motivations; indicate the outstanding problems where significant progress can be accomplished in the near future, leading to the identification of specific science goals for the coming decade;
and lay out the SWMI panel’s imperatives for actions that are needed to meet those goals.
9.3 SIGNIFICANT ACCOMPLISHMENTS OF THE PREVIOUS DECADE
9.3.1 Scientific Progression
The science of solar wind-magnetosphere interactions was established near the dawn of the space age,
only 50 years ago. Since that time, knowledge of the magnetosphere has grown tremendously, progressing
from discovery to understanding.
Early research focused on the discovery and exploration of the different regions that lie above Earth’s
atmosphere: the radiation belts, the plasmasphere, the plasma sheet, and the solar wind. As researchers
discovered these regions and the particle populations that define them, they sought to identify and understand the physical processes that accelerate and transport the particles. They also learned that the system
is not static, but rather exhibits substantial variability with identifiable patterns. It became clear that different regions are not independent, but rather are intimately linked, and the variability and processes in one
region can be clearly related to those in other regions.
Scientists now appreciate that the magnetosphere is a vast, highly coupled system that involves a
wide array of fundamental physical processes and complex linkages between different regions. In the past
decade this system’s impact on human technology and society has also come to be appreciated: storms
and other disturbances in geospace have significantly disrupted and disabled spacecraft and ground-based
power grids. Finally, as mankind has reached out to explore the solar system, researchers have discovered
that other solar system bodies possess magnetospheres that exhibit many of the same processes found near
Earth, but frequently manifested in different ways, and producing very different structure and dynamics.