Search Publications
Microwave Spectral Imaging of an Erupting Magnetic Flux Rope: Implications for the Standard Solar Flare Model in Three Dimensions
Reeves, Katharine K.; Chen, Bin; Yu, Sijie +1 more
We report microwave spectral imaging observations of an erupting magnetic flux rope during the early impulsive phase of the X8.2-class limb flare on 2017 September 10, obtained by the Expanded Owens Valley Solar Array. A few days prior to the eruption, when viewed against the disk, the flux rope appeared as a reverse S-shaped dark filament along t…
Hot Plasma Flows and Oscillations in the Loop-top Region During the 2017 September 10 X8.2 Solar Flare
Reeves, Katharine K.; Polito, Vanessa; Chen, Bin +4 more
In this study, we investigate motions in the hot plasma above the flare loops during the 2017 September 10 X8.2 flare event. We examine the region to the south of the main flare arcade, where there is data from the Interface Region Imaging Spectrograph (IRIS) and the Extreme ultraviolet Imaging Spectrometer (EIS) on Hinode. We find that there are …
Hinode/EIS Measurements of Active-region Magnetic Fields
Landi, E.; Li, W.; Hutton, R. +1 more
The present work illustrates the potential of a new diagnostic technique that allows the measurement of the coronal magnetic field strength in solar active regions by utilizing a handful of bright Fe X and Fe XI lines commonly observed by the high-resolution Hinode/EUV Imaging Spectrometer (EIS). The importance of this new diagnostic technique is …
Detection of the Strongest Magnetic Field in a Sunspot Light Bridge
Lagg, Andreas; Solanki, Sami K.; Castellanos Durán, J. S. +1 more
Traditionally, the strongest magnetic fields on the Sun have been measured in sunspot umbrae. More recently, however, much stronger fields have been measured at the ends of penumbral filaments carrying the Evershed and counter-Evershed flows. Superstrong fields have also been reported within a light bridge separating two umbrae of opposite polarit…
A First Spectroscopic Measurement of the Magnetic-field Strength for an Active Region of the Solar Corona
Brage, Tomas; Si, Ran; Li, Wenxian +3 more
For all involved in astronomy, the importance of monitoring and determining astrophysical magnetic-field strengths is clear. It is also a well-known fact that the corona magnetic fields play an important part in the origin of solar flares and the variations of space weather. However, after many years of solar corona studies, there is still no dire…
Imaging and Spectral Study on the Null Point of a Fan-spine Structure During a Solar Flare
Yang, Shuhong; Zhang, Jun; Zhong, Ze +3 more
Using the multi-instrument observations, we make the first simultaneous imaging and spectral study on the null point of a fan-spine magnetic topology during a solar flare. When magnetic reconnection occurs at the null point, the fan-spine configuration brightens in the (extreme-)ultraviolet channels. In the Hα images, the fan-spine structure is pa…
Sun-as-a-star Spectral Irradiance Observations of Transiting Active Regions
Toriumi, Shin; Cheung, Mark C. M.; DeRosa, Marc L. +3 more
Major solar flares are prone to occur in active-region (AR) atmospheres associated with large, complex, dynamically evolving sunspots. This points to the importance of monitoring the evolution of starspots, not only in visible but also in ultraviolet (UV) and X-rays, in understanding the origin and occurrence of stellar flares. To this end, we per…
Dynamics of Late-stage Reconnection in the 2017 September 10 Solar Flare
Judge, Philip G.; Long, David M.; Matthews, Sarah A. +2 more
In this multi-instrument paper, we search for evidence of sustained magnetic reconnection far beyond the impulsive phase of the X8.2-class solar flare on 2017 September 10. Using Hinode/EIS, CoMP, SDO/AIA, K-Cor, Hinode/XRT, RHESSI, and IRIS, we study the late-stage evolution of the flare dynamics and topology, comparing signatures of reconnection…
Possible Production of Solar Spicules by Microfilament Eruptions
Yurchyshyn, Vasyl; Moore, Ronald L.; Sterling, Alphonse C. +1 more
We examine Big Bear Solar Observatory (BBSO) Goode Solar Telescope (GST) high spatial resolution (0"06), high-cadence (3.45 s), Hα-0.8 Å images of central-disk solar spicules, using data of Samanta et al. We compare with coronal-jet chromospheric-component observations of Sterling et al. Morphologically, bursts of spicules, referred to as "enhance…
The Drivers of Active Region Outflows into the Slow Solar Wind
Golub, Leon; Winebarger, Amy R.; Warren, Harry P. +13 more
Plasma outflows from the edges of active regions have been suggested as a possible source of the slow solar wind. Spectroscopic measurements show that these outflows have an enhanced elemental composition, which is a distinct signature of the slow wind. Current spectroscopic observations, however, do not have sufficient spatial resolution to disti…