Focus Areas for STEREO Plasmas and their embedded magnetic
fields affect the formation, evolution and destiny of planets
and planetary systems. The heliosphere shields the solar system
from galactic cosmic radiation. Our habitable planet is shielded
by its magnetic fi eld, protecting it from solar and cosmic
particle radiation and from erosion of the atmosphere by the
solar wind. Planets without a shielding magnetic field, such as
Mars and Venus, are exposed to those processes and evolve
differently. And on Earth, the magnetic field changes strength
and configuration during its occasional polarity reversals,
altering the shielding of the planet from external radiation
sources. Understand the causes and subsequent evolution of solar
activity that affects Earth's space climate and environment. The
climate and space environment of Earth are significantly
determined by the impact of plasma, particle, and radiative
outputs from the Sun. Therefore, it is essential to understand
the Sun, determine how predictable so