Search Publications

Quasiperiodic Super-Alfvénic Slippage along Flare Ribbons Observed by the Interface Region Imaging Spectrograph

Hou, Yijun; Li, Ting; Zhou, Guiping +3 more

The apparent slipping motion of flare loops is regarded as a key feature of the 3D magnetic reconnection in the solar flares. The slippage with a super-Alfvénic speed could be defined as slipping–running reconnection, while the slippage with a sub-Alfvénic speed is called slipping reconnection. Due to the limitation of the observational instrument…

Temporal Evolution of a Network Jet's Physical Properties Inferred from FISS/GST and IRIS Observations

Yurchyshyn, Vasyl; Chae, Jongchul; Cho, Kyuhyoun +6 more

Small-scale jets, such as chromospheric and transition region (TR) network jets, are of great interest regarding coronal heating and solar wind acceleration. Spectroscopic analysis based on multiple spectral lines with different formation temperatures is essential for understanding the physical properties and driving mechanisms of jets. Here, we c…

ALMA Observations of Solar Spicules in a Polar Coronal Hole

Nindos, A.; White, S. M.; Shimojo, M. +2 more

We report observations of solar spicules at millimeter wavelengths (mm-λ) using the Atacama Large Millimeter/submillimeter Array (ALMA). These are supplemented by observations in optical, ultraviolet (UV), and extreme ultraviolet (EUV) wavelengths. The observations were made on 2018 December 25 of the northern polar coronal hole. ALMA obtained tim…

Solar Variability in the Mg II h and k Lines

Solanki, S. K.; Shapiro, A. I.; Krivova, N. A. +3 more

Solar irradiance and its variations in the ultraviolet (UV) control the photochemistry in Earth's atmosphere and influence Earth's climate. The variability in the Mg II h and k core-to-wing ratio, also known as the Mg II index, is highly correlated with the solar UV irradiance variability. Because of this, the Mg II index is routinely used as a pr…

Simultaneous Existence of Oscillations, Counterstreaming Flows, and Mass Injections in Solar Quiescent Prominences

Xu, Zhe; Xue, Zhike; Yan, Xiaoli +8 more

Solar prominences are very spectacular structures embedded in the tenuous and hot solar corona. Counterstreaming flows, a common feature in solar quiescent prominences, have been discovered for more than 20 yr. However, the mechanism driving the counterstreaming flows is still elusive. To unveil the nature of this phenomenon, we analyzed data of a…

On the Magnetic and Thermodynamic Properties of Dark Fibrils in the Chromosphere

Kriginsky, Matheus; Oliver, Ramon

Fibrillar structures are ubiquitous in the solar chromosphere. An accurate determination of their properties requires the use of advanced high-resolution observations, which are now becoming broadly available from different observatories. We exploit the capabilities of multi-atom, multiline spectropolarimetric inversions using the Stockholm Invers…