Juan M. Fontenla

TL;DR: In this article, the authors discussed the limitations of the hydrostatic and one-dimensional assumptions used and analyzed the determination of helium emission when diffusion is included, using transport coefficients estimated from kinetic theory to determine the helium departures from local ionization balance.

TL;DR: In this paper, high spectral and spatial resolution data and broadband spectroheliograms were used to show that the central reversal of the Lyman-alpha line is highly variable in depth and is frequently shifted, leading to asymmetric profiles.

TL;DR: In this article, the evolution of the vector magnetic field and the sunspot motions observed in AR 6555 during 23-26 Mar 1991 were studied, and it was shown that these changes made the flaring possible, and developed a scenario that can explain the origin of the magnetic free energy that was released in these flares.

TL;DR: In this article, the authors examined the physical processes behind sudden localized brightenings (or microflares) that occur within these active regions and their relation to surging activity, and suggested that localized energy deposition in a region of the chromosphere that heats the material and produces a pressure pulse.

TL;DR: In this article, lower bounds on the degree of impact Extreme Ultraviolet/Ultraviolet (EUV/UV) line polarization expected during solar flares were evaluated and it was shown that, in some flare models, the energetic electrons can produce an impact polarization of a few percent in EUV neutral helium lines (i.e., lambda lambda 522, 537, and 584 A).