Dear all,
you might be interested in our new paper Lörinčík et al. 2020:
Title: Plasma Diagnostics from Active Region and Quiet-Sun Spectra
Observed by Hinode/EIS: Quantifying the Departures from a Maxwellian
Distribution
Abstract: We perform plasma diagnostics, including that of the
non-Maxwellian κ-distributions, in several structures observed in the
solar corona by the Extreme-Ultraviolet Imaging Spectrometer (EIS) on
board the Hinode spacecraft. To prevent uncertainties due to the
…
[View More]in-flight calibration of EIS, we selected spectral atlases observed
shortly after the launch of the mission. One spectral atlas contains an
observation of an active region, while the other is an off-limb
quiet-Sun region. To minimize the uncertainties of the diagnostics, we
rely only on strong lines and average the signal over a spatial area
within selected structures. Multiple plasma parameters are diagnosed,
such as the electron density, the differential emission measure, and the
non-Maxwellian parameter κ. To do that, we use a simple, well-converging
iterative scheme based on refining the initial density estimates via the
differential emission measure (DEM) and κ. We find that while the
quiet-Sun spectra are consistent with a Maxwellian distribution, the
coronal loops and moss observed within the active region are strongly
non-Maxwellian with κ lap 3. These results were checked by calculating
synthetic ratios using DEMs obtained as a function of κ. Ratios
predicted using the DEMs assuming κ-distributions converged to the
ratios observed in the quiet Sun and coronal loops. To our knowledge,
this work presents a strong evidence of the presence of different
electron distributions between two physically distinct parts of the
solar corona.
Links:
https://arxiv.org/abs/2003.07091https://iopscience.iop.org/article/10.3847/1538-4357/ab8010
Sincerely,
Juraj Lörinčík
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