Dear all:

Please find a recent paper on Asymmetries in Coronal Spectral Lines and Emission Measure Distribution,
which Jim and Myself have recently submitted to ApJ. The abstract is appended below:

Abstract: It has previously been argued that 1. spicules do not provide enough preheated plasma to
fill the corona, and 2. even if they did, additional heating would be required to keep the plasma hot
as it expands upward. We here ad- dress the question of whether spicules play an important role by
injecting plasma at cooler temperatures (
< 2 MK), which then gets heated to coronal values at higher
altitudes. We measure red-blue asymmetries in line profiles formed over a wide range of temperatures
in the bright moss areas of two active regions. We derive emission measure distributions from the excess
wing emission. We find that the asymmetries and emission measures are small and conclude that spicules
do not inject an important (dominant) mass flux into the cores of active regions at temperatures
> 0.6 MK
(log
T > 5.8). These conclusions apply not only to spicules, but to any process that suddenly heats and
accelerates chromospheric plasma (e.g., a chromospheric nanoflare). The traditional picture of coronal
heating and chromospheric evaporation appears to remain the most likely explanation of the active region
corona.