by NASA

“ For example, nature possesses a number of ways to accelerate charged particles to very high energies. These energetic particles abound in solar flares, in Jupiter's magnetosphere, in supernovae, in galactic nuclei — and in Earth's own magnetosphere.
Thus, a careful study of geospace and the plasma processes that control its behavior applies not only to an understanding of solar-terrestrial relations and of their effects at Earth's surface, but also to basic scientific questions about plasmas.
DISRUPTIONS ON EARTH Energy flowing through geospace affects Earth on many time-scales. ”

“ Particle energy must be converted into electromagnetic waves. The same phenomena also occur on a vast scale in geospace. Geospace is the only easily accessible arena for studying nature's way with energy, not only here but throughout the universe.
Most of the universe is filled with plasma. Many actions that determine the structure and development of regions from small interstellar clouds to entire galaxies depend on basic interactions between plasmas and magnetic fields.
Interplanetary spacecraft have defined geospace—like magnetospheres around Mercury, Jupiter and Saturn. ”

“ This region, called geospace, extends to millions of kilometers around Earth and contains the atmosphere, the ionosphere, the magnetosphere and the near-Earth interplanetary medium.
Geospace is an integrated, strongly interactive system throughout which energy is continuously being generated, stored, transformed and released. Not only do geospace processes affect Earth's atmosphere and ground systems, but geospace is now known to be representative of plasma systems commonly found throughout the universe. ”

“ To understand the anatomy of the human body, students look at the structure of individual parts, one at a time. But to understand the relationships between the parts of the body -— its physiology — students must consider the living system as a whole. The whole is more complex than the simple sum of components because of the highly interactive nature of these parts. So it is with geospace. An understanding of geospace and of the interactions of its components requires a view of the entire system —— a view obtained by planned observations taken simultaneously in the key geospace regions. ”

“ Data from single spacecraft have led scientists through evolutionary stages — first discovery, then exploration sufficient to provide a schematic representation of the solar—terrestrial environment like the one to the right. It is now time to proceed to a comprehensive understanding of geospace dynamics with a multi—spacecraft mission that can return coordinated, simultaneous observations. ”

“ The different regions of geospace are populated by distinctly different plasma regimes. On the dayside of Earth at high latitudes, some magnetic lines of force part to form a funnel in the magnetosphere (the polar cusp region) that opens a channel down to Earth's surface. Through this funnel, energetic solar particles may plunge directly into the ionosphere and atmosphere. ”

“ By studying this incomplete picture, scientist have begun to appreciate the physical processes that must act to produce the interactions of various parts of geospace. Now they are using multiple spacecraft such as the three International Sun—Earth Explorers to collect data on the dynamic behavior of certain localized regions. An extended, multi—spacecraft program is necessary for the next step — to collect data on simultaneous events throughout geospace as a whole. ”

“ Plasma interactions are important throughout the solar system and the universe. Geospace uniquely provides an accessible example of a plasma environment in which significant processes can be studied directly. ”

“ ENERGY LABORATORY Geospace-like systems are common throughout the universe. Sizes range from Mercury's tiny magnetosphere to Jupiter's enormous one, larger than that of the Sun. Here, coordinates are labeled in units of the radius of the parent object; a typical value of the minimum dimension is given in kilometers. Geospace is at once a large—scale environment for studying processes that are hard to reproduce in miniature in Earth—bound laboratories, and a small—sca|e environment for studying events that are common throughout the universe. ”

“ These depict the relationship between the two plasma source regions and the two geospace storage regions. By placing a properly instrumented spacecraft laboratory in each of the four key regions, scientists can simultaneously observe the entry of plasma into the system, the storage and release of energy within the system, and the transfer of plasma and energy between those key regions as they change with time. ”

“ The energy stored by these groups of particles ultimately is responsible for Earth's magnetic storms.
With all this detail, scientists have little more than a sketch —an approximation built on a collection of independent, single—point measurements collected at different times during the past two decades. Boundaries are in constant motion. Changes in one region invariably stimulate subsequent changes or adjustments in other regions. ”

“ Designers of fusion reactors or advanced microwave radio transmitters are often challenged by problems in plasma physics. Plasmas must be accelerated to extreme energies. Energetic particles must be confined and transported. ”

“ The OPEN Program will be able to obtain much better science than other programs because of the new capacity to change orbits in space at will. The OPEN laboratories will be launched from the Space Shuttle and each of the OPEN spacecraft will include propulsion systems and ample fuel supplies for moves to different orbits. ”

“ Although a number of geospace effects have engineering solutions, an understanding of geospace to a level required for cause-effect predictions will greatly improve the operation of present facilities and the design and operation of future systems. ”

“ Diagram shows the extent to which geomagnetic storm currents in the ionosphere can induce currents in the windings of power station transformers; and a chart that suggests a correlation between high plains droughts and the 22-year solar cycle; a physical origin for such a relationship is not at all clear. ”

“ The PPL’s onboard propulsion system will drop the orbit later to a maximum altitude of about 25,000 kilometers so that direct measurements of the transfer of plasma between the ionospheric source region and the equatorial storage regions can be made. ”