ﻻ يوجد ملخص باللغة العربية
Large-scale propagating fronts are frequently observed during solar eruptions, yet it is open whether they are waves or not, partly because the propagation is modulated by coronal structures, whose magnetic field we still cannot measure. However, when a front impacts coronal structures, an opportunity arises for us to look into the magnetic properties of both interacting parties in the low-$beta$ corona. Here we studied large-scale EUV fronts accompanying three coronal mass ejections (CMEs), each originating from a kinking rope-like structure in the NOAA active region (AR) 12371. These eruptions were homologous and the surrounding coronal structures remained stationary. Hence we treated the events as one observed from three different viewing angles, and found that the primary front directly associated with the CME consistently transmits through 1) a polar coronal hole, 2) the ends of a crescent-shaped equatorial coronal hole, leaving a stationary front outlining its AR-facing boundary, and 3) two quiescent filaments, producing slow and diffuse secondary fronts. The primary front also propagates along an arcade of coronal loops and slows down due to foreshortening at the far side, where local plasma heating is indicated by an enhancement in 211 {AA} (Fe XIV) but a dimming in 193 {AA} (Fe XII) and 171 {AA} (Fe IX). The strength of coronal magnetic field is therefore estimated to be $sim,$2 G in the polar coronal hole and $sim,$4 G in the coronal arcade neighboring the active region. These observations substantiate the wave nature of the primary front and shed new light on slow fronts.
With the global view and high-cadence observations from SDO/AIA and STEREO, many spatially separated solar eruptive events appear to be coupled. However, the mechanisms for sympathetic events are still largely unknown. In this study, we investigate t
We present a statistical analysis of 43 coronal dimming events, associated with Earth-directed CMEs that occurred during the period of quasi-quadrature of the SDO and STEREO satellites. We studied coronal dimmings that were observed above the limb by
The Coronal Multichannel Polarimeter (CoMP) measures not only the polarization of coronal emission, but also the full radiance profiles of coronal emission lines. For the first time, CoMP observations provide high-cadence image sequences of the coron
Solar coronal dimmings have been observed extensively in the past two decades and are believed to have close association with coronal mass ejections (CMEs). Recent study found that coronal dimming is the only signature that could differentiate powerf
Coronal mass ejections (CMEs) are explosive events that occur basically daily on the Sun. It is thought that these events play a crucial role in the angular momentum and mass loss of late-type stars, and also shape the environment in which planets fo