Search Publications
Analysis of Geoeffective Impulsive Events on the Sun During the First Half of Solar Cycle 24
Wawrzaszek, Anna; Gil, Agnieszka; Modzelewska, Renata +4 more
A coronal mass ejection (CME) is an impulsive event that emerges rapidly from the Sun. We observed a quiet Sun without many spectacular episodes during the last decade. Although some fast halo and partial halo CMEs had taken place, among them was the backside CME on 23 July 2012. In this work, we verify the link between the variability of solar-wi…
Accuracy Analysis of the On-board Data Reduction Pipeline for the Polarimetric and Helioseismic Imager on the Solar Orbiter Mission
Hirzberger, Johann; Solanki, Sami K.; Woch, Joachim +4 more
Context: Scientific data reduction on-board deep space missions is a powerful approach to maximise science return, in the absence of wide telemetry bandwidths. The Polarimetric and Helioseismic Imager (PHI) on-board the Solar Orbiter (SO) is the first solar spectropolarimeter that opted for this solution, and provides the scientific community with…
Solar Soft X-Ray Irradiance Variability, II: Temperature Variations of Coronal X-Ray Features
Masuda, Satoshi; DeLuca, Edward; Kusano, Kanya +7 more
The temperature variations of the corona and its individual surface features as a function of the solar cycle are an interesting and important aspect of understanding the physics of the Sun. To study the temperature variations, we have used the full-disk soft X-ray images of the corona obtained from Hinode/X-Ray Telescope (XRT) in different filter…
Polarimetric Study of the Solar Corona During the Total Solar Eclipse on July 2, 2019 with a Liquid-Crystal Polarimeter
Fineschi, Silvano; Liberatore, Alessandro; Capobianco, Gerardo +5 more
The results obtained during the total Solar Eclipse on July 2, 2019, in Chile are presented together with the Eclipse K-corona Polarimeter (EKPol). The EKPol is equipped with an electro-optically modulating Liquid-Crystal Variable Retarder (LCVR) for the polarimetric observation of the solar corona. The use of this technology has been an important…
The Eruption of 22 April 2021 as Observed by Solar Orbiter: Continuous Magnetic Reconnection and Heating After the Impulsive Phase
Mierla, M.; Zhukov, A. N.; Berghmans, D. +33 more
We report on one of the first solar-eruptive events that was simultaneously observed by three of the remote-sensing instruments onboard Solar Orbiter during the cruise phase. The Extreme Ultraviolet Imager (EUI) observed an eruption on 22 April 2021. The corresponding CME was recorded by the coronagraph Metis. Finally, the Spectrometer/Telescope f…
The Evolution of Multipole Moments for the Global Solar Magnetic Field
Wang, Weihua; Chu, Zhe; Gu, Haihua
Based on synoptic magnetic maps, we use spherical harmonic functions to decompose the global magnetic field of the Sun. Through the expansion coefficients, the power spectrum Cl, and its zonal component ClZ and sectorial component ClS for order l are defined. Through two sampled synoptic maps,…
Analysis of Front Side Halo CMEs and Their Solar Source Active Region and Flare Ribbon Properties
Moon, Y. -J.; Shanmugaraju, A.; Ebenezer, E. +3 more
Halo coronal mass ejections (CMEs) from the Sun are the subset of CMEs, which are more energetic than the normal CMEs. Only the more energetic CMEs are observable in white-light coronagraphs when they are traveling along the line of sight (LOS) and a CME is better observed when it is traveling perpendicularly to the LOS. We investigated the flare …
Solar Energetic-Particle-Associated Coronal Mass Ejections Observed by the Mauna Loa Solar Observatory Mk3 and Mk4 Coronameters
St. Cyr, O. C.; Thompson, B. J.; Burkepile, J. T. +2 more
We report on the first comprehensive study of the coronal mass ejections (CMEs) associated with ∼25 MeV solar energetic-proton (SEP) events in 1980 - 2013 observed in the low/inner corona by the Mauna Loa Solar Observatory (MLSO) Mk3 and Mk4 coronameters. Where possible, these observations are combined with space-based observations from the Solar …
How Hot Can Small Solar Flares Get?
Krucker, Säm; Reeves, Katharine K.; Barczynski, Krzysztof +4 more
The temperature reached by solar flares is a key parameter to understanding the physical process that causes the energy release. In this work, we analysed data from a Hinode Observing Programme that focused on high cadence measurement of the flaring plasma. This was carried out when the X-ray imager and spectrometer (STIX) on Solar Orbiter was obs…
High-Resolution Spectral and Anisotropy Characteristics of Solar Protons During the GLE N∘73 on 28 October 2021 Derived with Neutron-Monitor Data Analysis
Vainio, Rami; Riihonen, Esa; Mishev, Alexander L. +4 more
The first ground-level enhancement of the current Solar Cycle 25 occurred on 28 October 2021. It was observed by several space-borne and ground-based instruments, specifically neutron monitors. A moderate count-rate increase over the background was observed by high-altitude polar stations on the South Pole and Dome C stations at the Antarctic plat…