R. Aznar Cuadrado
A5010599517- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Solar Radiation and Photovoltaics
- CCD and CMOS Imaging Sensors
- Astrophysics and Star Formation Studies
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Calibration and Measurement Techniques
- Photocathodes and Microchannel Plates
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
- Geomagnetism and Paleomagnetism Studies
- Astrophysical Phenomena and Observations
- Radiation Therapy and Dosimetry
- Infrared Target Detection Methodologies
- Dark Matter and Cosmic Phenomena
- History and Developments in Astronomy
- Spectroscopy Techniques in Biomedical and Chemical Research
- Advanced Fiber Optic Sensors
- Spacecraft Design and Technology
- Market Dynamics and Volatility
- Galaxies: Formation, Evolution, Phenomena
Max Planck Institute for Solar System Research
2014-2024
Max Planck Society
2003-2014
Max Planck Institute for Astronomy
2004
Armagh Observatory & Planetarium
2000-2002
Context. The Extreme Ultraviolet Imager (EUI) is part of the remote sensing instrument package ESA/NASA Solar Orbiter mission that will explore inner heliosphere and observe Sun from vantage points close to out ecliptic. advance “connection science” between solar activity heliosphere. Aims. With EUI we aim improve our understanding structure dynamics atmosphere, globally as well at high resolution, latitude perspectives. Methods. consists three telescopes, Full two High Resolution Imagers,...
Metis is the first solar coronagraph designed for a space mission capable of performing simultaneous imaging off-limb corona in both visible and UV light. The observations obtained with aboard Solar Orbiter ESA-NASA observatory will enable us to diagnose, unprecedented temporal coverage spatial resolution, structures dynamics full from 1.7 $R_\odot$ about 9 $R_\odot$. Due uniqueness profile, be able observe close vantage point (down 0.28 AU), achieving out-of-ecliptic views increase orbit...
The goal of this paper is to study the smallest brightening events observed in EUV quiet Sun. We use commissioning data taken by EUI instrument onboard recently launched Solar Orbiter mission. On 2020 May 30, was situated at 0.556AU from Its HRIEUV telescope 17.4nm passband reached an exceptionally high two-pixel spatial resolution 400km. size and duration small-scale structures determined data, while their height estimated triangulation with simultaneous SDO/AIA data. This first stereoscopy...
Switchbacks are sudden, large radial deflections of the solar wind magnetic field, widely revealed in interplanetary space by Parker Solar Probe. The switchbacks' formation mechanism and sources still unresolved, although candidate mechanisms include Alfv\'enic turbulence, shear-driven Kelvin-Helmholtz instabilities, interchange reconnection, geometrical effects related to spiral. This Letter presents observations from Metis coronagraph onboard Orbiter a single propagating S-shaped vortex,...
Coronal holes are areas on the Sun with open magnetic field lines. They a source region of solar wind, but how wind emerges from coronal is not known. We observed hole using Extreme Ultraviolet Imager Solar Orbiter spacecraft. identified jets scales few hundred kilometers, which last 20 to 100 seconds and reach speeds ~100 kilometers per second. The powered by reconnection have kinetic energy in picoflare range. intermittent widespread within hole. suggest that such could produce enough...
Abstract Magnetic reconnection is a key mechanism involved in solar eruptions and also prime possibility to heat the low corona millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations persistent null-point at scale about 390 km over one hour Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The show formation configuration above minor positive polarity embedded within region dominant negative near sunspot. gentle phase evidenced by sustained...
Solar wind, classified by its bulk speed and the Alfvénic nature of fluctuations, generates heliosphere. The elusive physical processes responsible for generation different types this wind are a topic active debate. Recent observations reveal intermittent jets, with kinetic energy in picoflare range, emerging from dark areas polar coronal hole threaded open magnetic field lines. These could substantially contribute to solar wind. However, their ubiquity direct links have not been...
Context. The Extreme Ultraviolet Imager (EUI), onboard Solar Orbiter consists of three telescopes: the two High Resolution Imagers in EUV (HRIEUV) and Lyman-{\alpha} (HRILya), Full Sun (FSI). Orbiter/EUI started its Nominal Mission Phase on 2021 November 27. Aims. EUI images from largest scales extended corona off limb, down to smallest features at base chromosphere. is therefore a key instrument for connection science that heart mission goals. Methods. highest resolution achieved when...
We have detected longitudinal magnetic fields between 2 and 4 kG in three (WD 0446-790, WD 1105-048, 2359-434) out of a sample 12 normal DA white dwarfs by using optical spectropolarimetry done with the VLT Antu 8 m telescope equipped FORS1. With exception 40 Eri B (4 kG) these are first positive detections below 30 kG. Although suspected, it was not clear whether significant fraction contain at this level. These may be explained as relics from main-sequence progenitors considerably enhanced...
The investigation of the wind in solar corona initiated with observations resonantly scattered UV emission coronal plasma obtained UVCS-SOHO, designed to measure outflow speed by applying Doppler dimming diagnostics. Metis on Solar Orbiter complements UVCS spectroscopic observations, performed during activity cycle 23, simultaneously imaging polarized visible light and HI Ly-alpha order obtain high-spatial temporal resolution maps outward velocity continuously expanding atmosphere. May 15,...
We study here the phenomena of decayless kink oscillations in a system active region (AR) coronal loops. Using high resolution observations from two different instruments, namely Extreme Ultraviolet Imager (EUI) on board Solar Orbiter and Atmospheric Imaging Assembly (AIA) Dynamics Observatory, we follow these AR loops for an hour each three consecutive days. Our results show significantly more resolved waves higher-resolution EUI data compared with AIA data. Furthermore, same exhibits many...
Relaxation of braided coronal magnetic fields through reconnection is thought to be a source energy heat plasma in active region loops. However, observations heating associated with an untangling braids remain sparse. One reason for this paucity could the lack sufficiently high spatial and temporal resolution capture process action. Using new (250-270 km on Sun) cadence (3-10 s) from Extreme Ultraviolet Imager (EUI) board Solar Orbiter, we observed small-scale different regions. The...
Abstract From 2022 March 18 to 21, NOAA Active Region (AR) 12967 was tracked simultaneously by Solar Orbiter at 0.35 au and Hinode/EIS Earth. During this period, strong blueshifted plasma upflows were observed along a thin, dark corridor of open magnetic field originating the AR’s leading polarity continuing toward southern extension northern polar coronal hole. A potential source surface model shows large lateral expansion corridor. Squashing factor Q -maps large-scale topology further...
Aims.We report on our analysis of the high resolution spectra () a sample 42 late-type active stars (with measured spanning from to ) acquired with Italian 3.6 m Telescopio Nazionale Galileo (TNG) using SARG spectrometer in 4960-10 110 Å range. The quality and good activity-level coverage allow us measure two different chromospheric indicators that can be derived Ca ii infrared triplet (Ca IRT) lines: residual equivalent width (EQW) indicator . aim this work is determine test best way...
The 3D fine structure of the solar atmosphere is still not fully understood as most available observations are taken from a single vantage point. goal paper to study distribution small-scale brightening events ("campfires") discovered in EUV quiet Sun by Extreme Ultraviolet Imager (EUI) aboard Solar Orbiter. We used first commissioning data set acquired EUI's High Resolution telescope on 30 May 2020 174 {\AA} passband and we combined it with simultaneous Atmospheric Imaging Assembly (AIA)...
The Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter (SO) spacecraft observed small extreme ultraviolet (EUV) bursts, termed campfires, that have been proposed to be brightenings near apexes of low-lying loops in quiet-Sun atmosphere. underlying magnetic processes driving these campfires are not understood. During cruise phase SO and at a distance 0.523\,AU from Sun, Polarimetric Helioseismic (SO/PHI) region jointly with SO/EUI, offering possibility investigate surface field...
Abstract This Letter reports the first observation of onset fully developed turbulence in solar corona. Long time series white-light coronal images, acquired by Metis aboard Solar Orbiter at 2 minutes cadence and spanning about 10 hr, were studied to gain insight into statistical properties fluctuations density plasma domain. From pixel-by-pixel spectral frequency analysis whole field view, scaling exponents derived. The results show that, over timescales ranging from 1 hr corresponding...
On October 28, 2021 the first X-class solar flare of Solar Cycle 25 occurred in active region NOAA AR 12887 with a peak at 15:35 UT. It produced rare event ground-level enhancement relativistic proton flux and global extreme ultraviolet wave, along fast halo coronal mass ejection (CME) as seen from Earth's perspective. A few hours before flare, slower CME had erupted quiet Sun just behind northwestern limb. Orbiter was almost aligned Sun-Earth line and, during synoptic campaign, its...
Context.Weak magnetic fields have been searched for on only a small number of white dwarfs. Current estimates find that about 10% all dwarfs in excess 1 MG; according to previous studies this increases up 25% the kG regime.
Context. Coronal rain is the most dramatic cooling phenomenon of solar corona. Recent observations in visible and UV spectrum have shown that coronal a pervasive active regions. Its strong link with heating through thermal non-equilibrium (TNE) – instability (TI) scenario makes it an essential diagnostic tool for properties. Another puzzling feature corona addition to its filamentary structure variability, particularly extreme (EUV). Aims. We aim identify observable features TNE-TI...
Coronal loops are the fundamental building blocks of solar corona. Therefore, comprehending their properties is essential in unraveling dynamics upper atmosphere. In this study, we conduct a comparative analysis morphology and coronal loop observed from two different spacecraft: High Resolution Imager (HRI EUV ) Extreme Ultraviolet on board Solar Orbiter, Atmospheric Imaging Assembly (AIA) Dynamics Observatory. These spacecraft were separated by 43° during observation. The main findings...
Aims. We present an analysis of the first connection mosaic made by SPICE instrument on board ESA/NASA Solar Orbiter mission March 2, 2022. The data will be used to map coronal composition that compared with in-situ measurements taken SWA/HIS establish origin solar wind plasma observed at Orbiter. spectral lines were chosen have varying sensitivity ionization potential (FIP) effect, and therefore radiances vary significantly depending whether elemental is or photospheric. investigate link...
We present high spatial and temporal resolution Ca ii 8542 Å observations of a kink wave in an on-disk chromospheric active region fibril. The properties the are similar to those observed off-limb spicules. From phase period we determine lower limit for field strength fibril located at edge sunspot be few hundred gauss. find indications that event was triggered by small-scale reconnection higher up atmosphere.
We study the velocity structure of penumbral filaments in deep photosphere to obtain direct evidence for convective nature sunspot penumbrae. A was observed at high spatial resolution with 1 m Swedish Solar Telescope photospheric C i 5380 Å absorption line. The Multi-Object Multi-Frame Blind Deconvolution method is used image restoration and straylight filtered out. report here discovery clear redshifts line multiple locations filaments. For example, bright head show larger concentrated...
Brightenings observed in the solar extreme-ultraviolet (EUV) images are generally interpreted as signatures of micro- or nanoflares occurring at transition region coronal temperatures. Recent observations with Extreme Ultraviolet Imager (EUI) on board Solar Orbiter have revealed smallest such brightenings (termed campfires) quiet-Sun corona. Analyzing EUI 174 {\AA} data a resolution about 400 km Sun cadence 5 s from 30-May-2020, we report here number cases where these campfires exhibit...