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Accelerating Multiframe Blind Deconvolution via Deep Learning
Asensio Ramos, Andrés; Kuckein, Christoph; Esteban Pozuelo, Sara
Ground-based solar-image restoration is a computationally expensive procedure that involves nonlinear optimization techniques. The presence of atmospheric turbulence produces perturbations in individual images that make it necessary to apply blind deconvolution techniques. These techniques rely on the observation of many short-exposure frames that…
Study of Forbush Decrease Recovery Times by the Payload for Antimatter Matter Exploration and Light-Nuclei Astrophysics (PAMELA) Experiment
Ricci, M.; Picozza, P.; Bazilevskaya, G. A. +37 more
A Forbush decrease (FD) is a sudden drop of cosmic-ray intensity arising as an effect of coronal mass ejection (CME) propagation in interplanetary space. The different physical properties of each CME cause variability in the FDs observed by scientific instruments. A comprehensive study of both phenomena is required to properly understand the proce…
Temporal and Latitudinal Variation in Penumbra-Umbra Ratios of the Sunspots: Analyses of RGO, Kodaikanal and Debrecen Databases
Takalo, Jouni
We study the latitudinal distribution and temporal evolution of the sunspot penumbra-umbra ratio (q ) for the even and odd Solar Cycles 12 - 24 of RGO sunspot groups, SC21 - SC24 of Debrecen sunspot groups and Kodaikanal sunspot dataset for SC16 - SC24. We find that RGO even (odd) Cycles have q -values 5.20 (4.75), Kodaikanal even (odd) cycles hav…
Study of Global Photospheric and Chromospheric Flows Using Local Correlation Tracking and Machine Learning Methods I: Methodology and Uncertainty Estimates
Xu, Yan; Denker, Carsten; Wang, Haimin +3 more
Cyclical variations of the solar magnetic fields, and hence the level of solar activity, are among the top interests of space weather research. Surface flows in global-scale, in particular differential rotation and meridional flows, play important roles in the solar dynamo that describes the origin and variation of solar magnetic fields. In princi…
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,…