arXiv subjects

Juan Carlos Trelles Arjona

Publications and source records attributed to Juan Carlos Trelles Arjona.

4 recordsLinked to original sources

arXiv2026

Measuring the Expansion of Solar Magnetic Fields with Multiline Inversions from Sunrise III

Magnetic fields in the solar atmosphere are expected to expand with height, forming magnetic canopies that couple the photosphere and chromosphere. Except for sunspots, direct measurements of this expansion remain scarce because they require simultaneous magnetic diagnostics over a broad range of atmospheric heights. We analyze four consecutive high-resolution spectropolarimetric raster scans of an emerging flux region observed with the Sunrise III/SCIP instrument. Simultaneous inversions of five photospheric Fe I lines and two chromospheric Ca II lines provide a quasi-continuous reconstruction of the magnetic field from the deep photosphere to the lower chromosphere. We apply a constant-flux method that follows the same magnetic flux through different atmospheric layers to quantify magnetic expansion. All three pores analyzed exhibit an overall increase in magnetic area with height, approximately doubling their cross section between the lower photosphere and the highest atmospheric layers sampled by the inversions. The expansion remains broadly stable throughout the 48-minute observing sequence. We further characterize the expansion with a quadratic parameterization and investigate its relation to pore properties. The three pores exhibit similar core magnetic field strengths but different expansion behaviors, indicating that the magnetic core strength alone does not determine the expansion. However, the present sample is too small to establish whether these differences are related to the thermodynamic or magnetic properties of the pores and their surroundings. These results demonstrate the potential of simultaneous multiline inversions for investigating the three dimensional magnetic topology of solar magnetic structures and provide the first direct measurements of the height-dependent magnetic expansion of solar pores.

astro-ph.SR↗

arXiv2025

Quiet Sun Magnetism from ViSP Data Multiline Inversions Around 630.1 nm

Quiet Sun magnetism plays an important role in the global energy balance of the solar atmosphere. The study of the magnetism of the quiet Sun has been a major effort in the last decades, and, as a result, very important advances in our knowledge have been achieved. The recent commissioning of the Daniel K. Inouye Solar Telescope, the largest ground-based solar telescope in the world today, provides us with data of high spectropolarimetric quality and high spatial resolution. The combination of data acquired with the ViSP instrument on the DKIST telescope around 630.1 nm and multiline inversions enables the achievement of exceptionally high spatial resolution in the solar atmosphere, both at the surface and in depth. In this paper we determine the log(gf) values of the spectral lines around 630.1 nm observed with the ViSP instrument and search for the best multi-inversion strategy, by means of MHD simulations, to analyze quiet Sun magnetism data within such spectral range. We present results of quiet Sun magnetism with special emphasis on its evolution with optical depth. In the internetwork, we find the decrease with height of the averaged magnetic field strength and the zone from which the fields become more horizontal. Additionally, we explore the depth-dependent evolution of the networks canopy, uncovering intriguing insights into its thermodynamic and magnetic properties. Notably, we detect a temperature enhancement in very localized areas of the vicinity of the network and distinguish mass motions with opposing velocities inside the flux tubes.

astro-ph.SR↗

arXiv2023

Solar-cycle and Latitude Variations in the Internetwork Magnetism

The importance of the quiet-Sun magnetism is that it is always there to a greater or lesser extent, being a constant provider of energy, independently of the solar cycle phase. The open questions about the quiet-Sun magnetism include those related to its origin. Most people claim that the local dynamo action is the mechanism that causes it. This fact would imply that the quiet-Sun magnetism is nearly the same at any location over the solar surface and at any time. Many works claim that the quiet Sun does not have any variation at all, although a few of them raise doubt on this claim and find mild evidence of a cyclic variation in the the quiet-Sun magnetism. In this work, we detect clear variations in the internetwork magnetism both with latitude and solar cycle. In terms of latitude, we find an increase in the averaged magnetic fields toward the solar poles. We also find long-term variations in the averaged magnetic field at the disk center and solar poles, and both variations are almost anticorrelated. These findings do not support the idea that the local dynamo action is the unique factory of the quiet-Sun magnetism.

astro-ph.SR↗

arXiv2017

Benchmarking the computing resources at the Instituto de Astrofísica de Canarias

The aim of this study is the characterization of the computing resources used by researchers at the "Instituto de Astrofísica de Canarias" (IAC). Since there is a huge demand of computing time and we use tools such as HTCondor to implement High Throughput Computing (HTC) across all available PCs, it is essential for us to assess in a quantitative way, using objective parameters, the performances of our computing nodes. In order to achieve that, we have run a set of benchmark tests on a number of different desktop and laptop PC models among those used in our institution. In particular, we run the "Polyhedron Fortran Benchmarks" suite, using three different compilers: GNU Fortran Compiler, Intel Fortran Compiler and the PGI Fortran Compiler; execution times are then normalized to the reference values published by Polyhedron. The same tests were run multiple times on a same PCs, and on 3 to 5 PCs of the same model (whenever possible) to check for repeatability and consistency of the results. We found that in general execution times, for a given PC model, are consistent within an uncertainty of about 10%, and show a gain in CPU speed of a factor of about 3 between the oldest PCs used at the IAC (7-8 years old) and the newest ones.

cs.PF↗