  The purpose of this white paper is to put together a coherent vision for the
role of helioseismic monitoring of magnetic activity in the Sun's far
hemisphere that will contribute to improving space weather forecasting as well
as fundamental research in the coming decade. Our goal fits into the broader
context of helioseismology in solar research for any number of endeavors when
helioseismic monitors may be the sole synoptic view of the Sun's far
hemisphere. It is intended to foster a growing understanding of solar activity,
as realistically monitored in both hemispheres, and its relationship to all
known aspects of the near-Earth and terrestrial environment. Some of the
questions and goals that can be fruitfully pursued through seismic monitoring
of farside solar activity in the coming decade include: What is the
relationship between helioseismic signatures and their associated magnetic
configurations, and how is this relationship connected to the solar EUV
irradiance over the period of a solar rotation?; How can helioseismic
monitoring contribute to data-driven global magnetic-field models for precise
space weather forecasting?; What can helioseismic monitors tell us about
prospects of a flare, CME or high-speed stream that impacts the terrestrial
environment over the period of a solar rotation?; How does the inclusion of
farside information contribute to forecasts of interplanetary space weather and
the environments to be encountered by human crews in interplanetary space?
Thus, it is crucial for the development of farside monitoring of the Sun be
continued into the next decade either through ground-based or space-borne
observations.
