[Loops] A paper on Asymmetries in Coronal Spectral Lines and Emission Measure Distribution

[Durgesh Tripathi]

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.

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