[Loops] New paper on nanoflare flows and EUV spectral lines

[Marcelo Lopez Fuentes]

Dear all,

Here I share with you the abstract and astro-ph link of a paper recently
accepted for publication in ApJ. Perhaps some of you had the change to see
a poster of this work that Jim presented at the last Loops Workshop in
Paris.

I hope you are all doing well!
Best regards,
Marcelo

Astro-ph link: http://arxiv.org/abs/2210.01896

Title: The effect of nanoflare flows on EUV spectral lines

Authors: Marcelo López Fuentes(1), James A. Klimchuk(2)
(1) Instituto de Astronomia y Fisica del Espacio (IAFE), Argentina (2)
NASA Goddard Space Flight Center

Abstract: The nanoflare model of coronal heating is one of the most
successful scenarios to explain, within a single framework, the diverse
set of coronal observations available with the present instrument
resolutions. The model is based on the idea that the coronal structure is
formed by elementary magnetic strands which are tangled and twisted by the
displacement of their photospheric footpoints by convective motions. These
displacements inject magnetic stress between neighbor strands that
promotes current sheet formation, reconnection, plasma heating, and
possibly also particle acceleration. Among other features, the model
predicts the ubiquitous presence of plasma flows at different
temperatures. These flows should, in principle, produce measurable effects
on observed spectral lines in the form of Doppler-shifts, line asymmetries
and non-thermal broadenings. In this work we use a Two-Dimensional
Cellular Automaton Model (2DCAM) developed in previous works, in
combination with the Enthalpy Based Thermal Evolution of Loops (EBTEL)
model, to analyze the effect of nanoflare heating on a set of known EUV
spectral lines. We find that the complex combination of the emission from
plasmas at different temperatures, densities and velocities, in
simultaneously evolving unresolved strands, produces characteristic
properties in the constructed synthetic lines, such as Doppler-shifts and
non-thermal velocities up to tens of km s−1 for the higher analyzed
temperatures. Our results might prove useful to guide future modeling and
observations, in particular, regarding the new generation of proposed
instruments designed to diagnose plasmas in the 5 to 10 MK temperature
range.