  We examine the different element abundances exhibited by the closed loop
solar corona and the slow speed solar wind. Both are subject to the First
Ionization Potential (FIP) Effect, the enhancement in coronal abundance of
elements with FIP below 10 eV (e.g. Mg, Si, Fe) with respect to high FIP
elements (e.g. O, Ne, Ar), but with subtle differences. Intermediate elements,
S, P, and C, with FIP just above 10 eV, behave as high FIP elements in closed
loops, but are fractionated more like low FIP elements in the solar wind. On
the basis of FIP fractionation by the ponderomotive force in the chromosphere,
we discuss fractionation scenarios where this difference might originate.
Fractionation low in the chromosphere where hydrogen is neutral enhances the S,
P and C abundances. This arises with nonresonant waves, which are ubiquitous in
open field regions, and is also stronger with torsional Alfven waves, as
opposed to shear (i.e. planar) waves. We discuss the bearing these findings
have on models of interchange reconnection as the source of the slow speed
solar wind. The outflowing solar wind must ultimately be a mixture of the
plasma in the originally open and closed fields, and the proportions and degree
of mixing should depend on details of the reconnection process. We also
describe novel diagnostics in ultraviolet and extreme ultraviolet spectroscopy
now available with these new insights, with the prospect of investigating slow
speed solar wind origins and the contribution of interchange reconnection by
remote sensing.
