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Super-Resolution of SOHO/MDI Magnetograms of Solar Active Regions Using SDO/HMI Data and an Attention-Aided Convolutional Neural Network
Xu, Yan; Wang, Haimin; Wang, Jason T. L. +4 more
Image super-resolution is an important subject in image processing and recognition. Here, we present an attention-aided convolutional neural network for solar image super-resolution. Our method, named SolarCNN, aims to enhance the quality of line-of-sight (LOS) magnetograms of solar active regions (ARs) collected by the Michelson Doppler Imager (M…
Improving the Spectral Resolution and Wavelength Scale of SDO/EVE MEGS-A Flare Observations
Chamberlin, Phillip; Gonzalez, Gabriela; Herde, Vicki
The Extreme ultraviolet Variability Experiment (EVE) is one of three instruments onboard the Solar Dynamics Observatory (SDO). This paper focuses on using the "A" channel on the Multiple EUV Grating Spectrographs (MEGS-A) on EVE, which measures wavelengths of 5 – 37 nm, to improve the wavelength scale accuracy and spectral resolution during solar …
Solar Soft X-ray Irradiance Variability III: Magnetic Field Variations of Coronal X-ray Features
Matsumoto, Takuma; Masuda, Satoshi; DeLuca, Edward +7 more
The magnetic field changes the radiative output of the Sun and is the main source for all the solar surface features. To study the role of the underlying photospheric magnetic field in relation to emission features observed in the solar corona, we have used the full-disk soft X-ray images from Hinode/X-Ray Telescope (Hinode/XRT) and the magnetogra…
The First Survey of Quiet Sun Features Observed in Hard X-Rays with NuSTAR
Krucker, Säm; White, Stephen M.; Grefenstette, Brian W. +5 more
We present the first survey of quiet Sun features observed in hard X-rays (HXRs), using the Nuclear Spectroscopic Telescope ARray (NuSTAR), a HXR focusing optics telescope. The recent solar minimum, combined with NuSTAR's high sensitivity, has presented a unique opportunity to perform the first HXR imaging spectroscopy on a range of features in th…
Small-Scale Upflows in a Coronal Hole - Tracked from the Photosphere to the Corona
Barczynski, Krzysztof; Orozco Suárez, David; Mandrini, Cristina H. +4 more
Coronal transients are known as sources of coronal upflows. With the commissioning of Solar Orbiter, it became apparent that coronal small-scale features are even more frequent than previously estimated. It was found that even small coronal features seen by Solar Orbiter can produce visible upflows. Therefore, it is important to study the plasma f…
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…
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…
Observation of the Solar Corona Using Radio Scintillation with the Akatsuki Spacecraft: Difference Between Fast and Slow Wind
Matsumoto, Takuma; Pätzold, Martin; Imamura, Takeshi +8 more
The properties of the coronal plasma at heliocentric distances of 1.5 - 8.9 R⊙ (solar radii) were studied with radio-occultation observations using JAXA's Akatsuki spacecraft in 2016. Physical parameters that characterize the solar wind were retrieved from the intensity-scintillation time series by fitting a theoretical spectrum to the …
Searching for a Solar Source of Magnetic-Field Switchbacks in Parker Solar Probe's First Encounter
Mandrini, C. H.; Raouafi, N. E.; Velli, M. +9 more
Parker Solar Probe observations show ubiquitous magnetic-field reversals closer to the Sun, often referred to as "switchbacks". The switchbacks have been observed before in the solar wind near 1 AU and beyond, but their occurrence was historically rare. PSP measurements below ∼ 0.2 AU show that switchbacks are, however, the most prominent structur…
Spectral Lines in FUV and EUV for Diagnosing Coronal Magnetic Field
Nagaraju, K.; Khan, Raveena
The diagnostic capabilities of spectral lines in the far-ultraviolet (FUV) and extreme-ultraviolet (EUV) wavelength ranges are explored in terms of their Hanle and Zeeman sensitivity to probe the vector magnetic fields in the solar corona. The temperature range covered is log10(T)=5.5 - 6.3. The circular-polarization signal due to longi…