Miguel Rojas-Quesada
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Miguel Rojas-Quesada has a total of 13 co-authors. Here are the top co-authors by number of shared publications:
- Atsuki Shinbori
Institute for Space‐Earth Environmental Research Nagoya University Nagoya Japan
1 shared publication - Fabiano S. Rodrigues
W. B. Hanson Center for Space Sciences The University of Texas at Dallas Richardson TX USA
1 shared publication - Hugh S. Hudson
University of Glasgow
1 shared publication - Jonas Sousasantos
William B. Hanson Center for Space Sciences University of Texas at Dallas—UT Dallas Richardson TX USA
1 shared publication - Josemaria Gomez Socola
W.B. Hanson Center for Space Sciences, The University of Texas at Dallas, Dallas, 75080, United States
1 shared publication - Lyndsay Fletcher
University of Glasgow
1 shared publication
Latest Publications
- Open Access
- 8 May 2026
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 549 (2)
First time delay observation between two mid-infrared channels in solar flare footpoints
The strong correlation between energy injection and mid-infrared (mid-IR) emission observed during solar flares can be used to probe energy deposition throughout the chromosphere, since the IR tracks prompt flare-induced changes in electron density. Despite its diagnostic value, solar mid-IR observations are relatively recent, with sporadic campaigns over the last decade resulting in only a few recorded flares. Earlier studies found time lags between mid-IR emissions from spatially resolved footpoints, offering clues about flare energy transport. Building on this, we analyse the time lags between emissions at two wavelengths (5.2 and 8.2 $\mu$m) for each footpoint. Using a local cross-correlation function, we show for the first time that the 8.2 $\mu$m emission channel peaks 0.3–0.45 $\mathrm{s}$ before the 5.2 $\mu$m channel. We investigate the origin of this lag, obtaining infrared emission estimates using results from the RADYN radiation hydrodynamics code. The theoretical lag values fall within the range of the observed ones. Variations in opacity primarily due to flare-induced ionization explain the wavelength-dependent temporal shift between emission maxima. In particular, longer wavelengths exhibit a smaller lag between the peak of energy injection and peak of intensity. These results contribute to a better understanding of how energy deposition during a flare affects the chromospheric layers of the atmosphere. Future observations with higher temporal resolution could exploit measurements of these time lags to more fully characterize the dynamics of energy deposition during solar flares, opening a new avenue for studying heating and energy transport processes in the solar atmosphere.- 8 May 2026
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 549 (2)
Open AccessFirst time delay observation between two mid-infrared channels in solar flare footpoints
The strong correlation between energy injection and mid-infrared (mid-IR) emission observed during solar flares can be used to probe energy deposition throughout the chromosphere, since the IR tracks prompt flare-induced changes in electron density. Despite its diagnostic value, solar mid-IR observations are relatively recent, with sporadic campaigns over the last decade resulting in only a few recorded flares. Earlier studies found time lags between mid-IR emissions from spatially resolved footpoints, offering clues about flare energy transport. Building on this, we analyse the time lags between emissions at two wavelengths (5.2 and 8.2 $\mu$m) for each footpoint. Using a local cross-correlation function, we show for the first time that the 8.2 $\mu$m emission channel peaks 0.3–0.45 $\mathrm{s}$ before the 5.2 $\mu$m channel. We investigate the origin of this lag, obtaining infrared emission estimates using results from the RADYN radiation hydrodynamics code. The theoretical lag values fall within the range of the observed ones. Variations in opacity primarily due to flare-induced ionization explain the wavelength-dependent temporal shift between emission maxima. In particular, longer wavelengths exhibit a smaller lag between the peak of energy injection and peak of intensity. These results contribute to a better understanding of how energy deposition during a flare affects the chromospheric layers of the atmosphere. Future observations with higher temporal resolution could exploit measurements of these time lags to more fully characterize the dynamics of energy deposition during solar flares, opening a new avenue for studying heating and energy transport processes in the solar atmosphere. - Open Access
- 30 January 2026
- Published by Springer Nature in Solar Physics
- Vol. 301 (2) , 21
A Proof-of-Concept Technique for Detection of Stellar Eruptive Prominences in Photometric Observations Using Insights from Solar EUV Data in He II 304 Å
Stellar eruptive prominences are one of the key components shaping stellar space weather environments. Moreover, due to the association of eruptive prominences with coronal mass ejections and their degrading influence on planetary atmospheres, they play a crucial role in the habitability of exoplanets. In this article, we used the insights from solar extreme-ultraviolet (EUV) observations to develop and test a technique for the detection of stellar eruptive prominences. We focused on the EUV imaging observations of the entire Sun provided by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) in the 304 Å channel. For this proof-of-concept study, we selected only a few examples of solar eruptive prominences and minor solar flares and analysed them in the Sun-as-a-star mode that mimics the stellar EUV photospheric observations. To validate the results obtained from the SDO/AIA Sun-as-a-star analysis, we used the SDO/Extreme Ultraviolet Variability Experiment (EVE) irradiance measurements. Our analysis showed markable intensity enhancements in the SDO/AIA 304 Å light curves during the prominence eruptions, with intensity increasing gradually for tens of minutes to several hours with enhancements of up to 1.5%. Flares exhibited a significantly faster intensity increase phase (a few minutes long) leading to large enhancements in the 304 Å channel of up to 8%. The large difference in the duration of the 304 Å intensity rise phases suggests that EUV stellar photometry in the He ii 304 Å line can provide signatures clearly attributable to stellar prominence eruptions or flares. However, development of robust techniques for detection of stellar eruptive prominences using the insights from EUV solar observations will require significantly broader statistical analyses that are beyond the scope of this work.
- 30 January 2026
- Published by Springer Nature in Solar Physics
- Vol. 301 (2) , 21
Open AccessA Proof-of-Concept Technique for Detection of Stellar Eruptive Prominences in Photometric Observations Using Insights from Solar EUV Data in He II 304 Å
Stellar eruptive prominences are one of the key components shaping stellar space weather environments. Moreover, due to the association of eruptive prominences with coronal mass ejections and their degrading influence on planetary atmospheres, they play a crucial role in the habitability of exoplanets. In this article, we used the insights from solar extreme-ultraviolet (EUV) observations to develop and test a technique for the detection of stellar eruptive prominences. We focused on the EUV imaging observations of the entire Sun provided by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) in the 304 Å channel. For this proof-of-concept study, we selected only a few examples of solar eruptive prominences and minor solar flares and analysed them in the Sun-as-a-star mode that mimics the stellar EUV photospheric observations. To validate the results obtained from the SDO/AIA Sun-as-a-star analysis, we used the SDO/Extreme Ultraviolet Variability Experiment (EVE) irradiance measurements. Our analysis showed markable intensity enhancements in the SDO/AIA 304 Å light curves during the prominence eruptions, with intensity increasing gradually for tens of minutes to several hours with enhancements of up to 1.5%. Flares exhibited a significantly faster intensity increase phase (a few minutes long) leading to large enhancements in the 304 Å channel of up to 8%. The large difference in the duration of the 304 Å intensity rise phases suggests that EUV stellar photometry in the He ii 304 Å line can provide signatures clearly attributable to stellar prominence eruptions or flares. However, development of robust techniques for detection of stellar eruptive prominences using the insights from EUV solar observations will require significantly broader statistical analyses that are beyond the scope of this work.
- Open Access
- 3 June 2025
- Published by American Geophysical Union (AGU) in Space Weather
- Vol. 23 (6)
On the Extraordinary L‐Band Scintillation Event Observed in the American Sector During the 23–24 March 2023 Geomagnetic Storm
We report an extraordinary L‐band scintillation event detected in the American sector on the night of 23–24 March 2023. The event was detected using observations distributed from the magnetic equator to mid latitudes. The observations were made by ionospheric scintillation and total electron content (TEC) monitors deployed at the Jicamarca Radio Observatory (JRO, ∼−1° dip latitude), at the Costa Rica Institute of Technology (CRT, ∼20° dip latitude), and at The University of Texas at Dallas (UTD, ∼42° dip latitude). The observations show intense pre‐ and post‐midnight scintillations at JRO, a magnetic equatorial site where L‐band scintillation is typically weak and limited to pre‐midnight hours. The observations also show long‐lasting extremely intense L‐band scintillations detected by the CRT monitor. Additionally, the rare occurrence of intense mid‐latitude scintillation was detected by the UTD monitor around local midnight. Understanding of the ionospheric conditions leading to scintillation was assisted by TEC and rate of change of TEC index (ROTI) maps. The maps showed that the observed scintillation event was caused by equatorial plasma bubble (EPB)‐like ionospheric depletions reaching mid latitudes. TEC maps also showed the occurrence of an enhanced equatorial ionization anomaly throughout the night indicating the action of disturbance electric fields and creating conditions that favor the occurrence of severe scintillation. Additionally, the ROTI maps confirm the occurrence of pre‐ and post‐midnight EPBs that can explain the long duration of low latitude scintillation. The observations describe the spatio‐temporal variation and quantify the severity of the scintillation impact of EPB‐like disturbances reaching mid latitudes.
- 3 June 2025
- Published by American Geophysical Union (AGU) in Space Weather
- Vol. 23 (6)
Open AccessOn the Extraordinary L‐Band Scintillation Event Observed in the American Sector During the 23–24 March 2023 Geomagnetic Storm
We report an extraordinary L‐band scintillation event detected in the American sector on the night of 23–24 March 2023. The event was detected using observations distributed from the magnetic equator to mid latitudes. The observations were made by ionospheric scintillation and total electron content (TEC) monitors deployed at the Jicamarca Radio Observatory (JRO, ∼−1° dip latitude), at the Costa Rica Institute of Technology (CRT, ∼20° dip latitude), and at The University of Texas at Dallas (UTD, ∼42° dip latitude). The observations show intense pre‐ and post‐midnight scintillations at JRO, a magnetic equatorial site where L‐band scintillation is typically weak and limited to pre‐midnight hours. The observations also show long‐lasting extremely intense L‐band scintillations detected by the CRT monitor. Additionally, the rare occurrence of intense mid‐latitude scintillation was detected by the UTD monitor around local midnight. Understanding of the ionospheric conditions leading to scintillation was assisted by TEC and rate of change of TEC index (ROTI) maps. The maps showed that the observed scintillation event was caused by equatorial plasma bubble (EPB)‐like ionospheric depletions reaching mid latitudes. TEC maps also showed the occurrence of an enhanced equatorial ionization anomaly throughout the night indicating the action of disturbance electric fields and creating conditions that favor the occurrence of severe scintillation. Additionally, the ROTI maps confirm the occurrence of pre‐ and post‐midnight EPBs that can explain the long duration of low latitude scintillation. The observations describe the spatio‐temporal variation and quantify the severity of the scintillation impact of EPB‐like disturbances reaching mid latitudes.