Search Publications
Unexpected major geomagnetic storm caused by faint eruption of a solar trans-equatorial flux rope
Zhang, Qingmin; Ji, Haisheng; Su, Yingna +1 more
Some geomagnetic storms' solar origins are ambiguous, making them hard to predict. On March 23, 2023, a severe geomagnetic storm occurred, however, forecasts based on remote-sensing observations failed to predict it. Here, we show clear evidence that this storm originates from the eruption of a trans-equatorial, longitudinal and low-density magnet…
Fast plasmoid-mediated reconnection in a solar flare
Feng, Xueshang; Song, Yongliang; Xue, Zhike +8 more
Magnetic reconnection is a multi-faceted process of energy conversion in astrophysical, space and laboratory plasmas that operates at microscopic scales but has macroscopic drivers and consequences. Solar flares present a key laboratory for its study, leaving imprints of the microscopic physics in radiation spectra and allowing the macroscopic evo…
Evidence of ubiquitous Alfvén pulses transporting energy from the photosphere to the upper chromosphere
Wang, Yuming; Liu, Jiajia; Erdélyi, Robert +2 more
The multi-million degree temperature increase from the middle to the upper solar atmosphere is one of the most fascinating puzzles in plasma-astrophysics. Although magnetic waves might transport enough energy from the photosphere to heat up the local chromosphere and corona, observationally validating their ubiquity has proved challenging. Here, w…
Formation and dynamics of a solar eruptive flux tube
Kusano, Kanya; Inoue, Satoshi; Büchner, Jörg +1 more
Solar eruptions are well-known drivers of extreme space weather, which can greatly disturb the Earth's magnetosphere and ionosphere. The triggering process and initial dynamics of these eruptions are still an area of intense study. Here we perform a magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reve…
A Solar cycle correlation of coronal element abundances in Sun-as-a-star observations
Warren, Harry P.; Brooks, David H.; Baker, Deborah +1 more
The elemental composition in the coronae of low-activity solar-like stars appears to be related to fundamental stellar properties such as rotation, surface gravity, and spectral type. Here we use full-Sun observations from the Solar Dynamics Observatory, to show that when the Sun is observed as a star, the variation of coronal composition is highl…
Observing the release of twist by magnetic reconnection in a solar filament eruption
Zhang, Jun; Bi, Yi; Xue, Zhike +9 more
Magnetic reconnection is a fundamental process of topology change and energy release, taking place in plasmas on the Sun, in space, in astrophysical objects and in the laboratory. However, observational evidence has been relatively rare and typically only partial. Here we present evidence of fast reconnection in a solar filament eruption using hig…
Full-Sun observations for identifying the source of the slow solar wind
Warren, Harry P.; Ugarte-Urra, Ignacio; Brooks, David H.
Fast (>700 km s-1) and slow (~400 km s-1) winds stream from the Sun, permeate the heliosphere and influence the near-Earth environment. While the fast wind is known to emanate primarily from polar coronal holes, the source of the slow wind remains unknown. Here we identify possible sites of origin using a slow solar wind s…
Using the transit of Venus to probe the upper planetary atmosphere
Piccioni, Giuseppe; Reale, Fabio; Widemann, Thomas +3 more
During a planetary transit, atoms with high atomic number absorb short-wavelength radiation in the upper atmosphere, and the planet should appear larger during a primary transit observed in high-energy bands than in the optical band. Here we measure the radius of Venus with subpixel accuracy during the transit in 2012 observed in the optical, ultr…