E. Edge of the Heliosphere
•The partially ionized LISM and the solar wind are
separated
by a complex set of plasma and neutral atom
boundaries of
enormous scale, located between ~90 and
~250 AU from the sun.
•The first of these boundaries, the HYDROGEN WALL, a wall of
interstellar neutral hydrogen slightly more
than twice the interstellar
density and some 100 AU wide, has been
detected. Offered the first
glimpse into the global structure of the 3D
heliosphere.
HOW: The detection of the hydrogen wall resulted from the
serendipitous convergence of predictive theoretical
modeling,
observations that tried to place limits on the D/H ratio,
and a
multi-disciplinary approach