Stereoscopic Observations of an Erupting Mini-filament-driven Two-sided-loop Jet and the Applications for Diagnosing a Filament Magnetic Field

Abstract

The ubiquitous solar jets or jet-like activities are generally regarded as an important source of energy and mass input to the upper solar atmosphere and the solar wind. However, questions about their triggering and driving mechanisms are not completely understood. By taking advantage of high temporal and high spatial resolution stereoscopic observations taken by the Solar Dynamic Observatory (SDO) and the Solar Terrestrial Relations Observatory (STEREO), we report an intriguing two-sided-loop jet occurred on 2013 June 02, which was dynamically associated with the eruption of a mini-filament below an overlying large filament, and two distinct reconnection processes are identified during the formation stage. The SDO observations reveals that the two-sided-loop jet showed a concave shape with a projection speed of about 80 -136 km s −1 . From the other view angle, the STEREO ahead observations clearly showed that the trajectory of the two arms of the two-sided-loop were along the cavity magnetic field lines hosting the large filament. Contrary to the well-accepted theoretical model, the present observation sheds new light on our understanding of the formation mechanism of two-sided-loop jets. Moreover, the eruption of the two-sided-loop jet not only supplied mass to the overlying large filament, but also provided a rare opportunity to diagnose the magnetic structure of the overlying large filament via the method of three-dimensional reconstruction.

Observation and modelling of solar jets

“…So far, the finding of blowout jets has been confirmed by many observational studies, and now we recognize that the vast majority of solar jets are caused by magnetic flux cancellation rather than flux emergence [63,[69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84]. Recently, high-resolution observational studies have shown that two-sided-loop jets are also associated with flux cancellations and include the eruption of mini-filaments inside the base arches [44,46,49,85,86], and two-sidedloop jets occurring in filament channels may be important for causing the eruption of large filaments [87].…”

“…An anemone jet exhibits an inverted-Y shape consisting of a straight plasma beam and a bright dome-like base. By contrast, a two-sided-loop jet appears as a pair of plasma beams ejecting in opposite directions from the eruption source region [44][45][46][47][48][49]. Recently, high-resolution observations combined with extrapolated three-dimensional (3D) coronal magnetic fields revealed the fan-spine topology magnetic system of straight anemone jets [50], which consists of a coronal nullpoint, a dome-like fan that represents the [51][52][53][54][55][56][57][58][59][60].…”

“…Previously, the delayed appearance of the cool component was explained as the cooling of the earlier, hotter one [115,117,125], the emerging chromospheric or transition region cool plasma accelerated the magnetic tension force of the newly formed magnetic reconnection field lines [123,127,129] or the different Alfvén speeds in the cool (high-density, low Alfvén speed) and hot (low-density, high Alfvén speed) plasma flows [130]. Based on high-spatio-temporal-resolution observations (figure 2d5), several works have provided evidence that the cool component of jets is directly formed by the erupting mini-filaments confined within the jet base [36,38,39,44,[62][63][64]69,74,109,131]. According to the interpretation of Shen et al [44,63,69], a mini-filament is confined by a small arch surrounded by open field lines.…”

“…Based on high-spatio-temporal-resolution observations (figure 2d5), several works have provided evidence that the cool component of jets is directly formed by the erupting mini-filaments confined within the jet base [36,38,39,44,[62][63][64]69,74,109,131]. According to the interpretation of Shen et al [44,63,69], a mini-filament is confined by a small arch surrounded by open field lines. For some reason, the arch starts to reconnect with the ambient open field lines (external reconnection), which produces the hot jet component like the generation of a standard jet.…”

“…Panesar et al [98] argued that the reason for flux emergence not directly causing jets is because the speed of emergence is seldom, if ever, fast enough. The emerging-reconnection scenario was challenged by the discovery of blowout jets that often involve the eruption of mini-filaments or filament channels [36,62,63,69,97] in association with flux cancellations [44,66,68,247,[304][305][306][307][308], and the cool component of blowout jets is actually the erupting filament material itself [44,63,69] rather than chromospheric material carried up by the emerging flux and accelerated by the show the direction of movement of the magnetic field lines, and features including the X-point, slow and fast shocks, and cool and hot jets are indicated [140].…”