Large‐Scale Current Sheets in Flares and CMEs

Can the Parker Solar Probe Detect a CME-flare Current Sheet?

“…After analyzing a set of unique data for several eruptions observed by the Ultraviolet Coronagraph Spectrometer (UVCS; Kohl et al 1995) and the Large Angle and Spectrometric Coronagraph Experiment (LASCO; Brueckner et al 1995) on the Solar and Heliospheric Observatory, on the other hand, Lin et al (2007Lin et al ( , 2009 found that, in some circumstances, the CSs are observable, and their thickness in real events could be as large as a few 10 4 km or even 10 5 km. Many follow-ups on this topic, by different authors for different events observed in different wavelengths by different instruments, both in space and on the ground, have given similar results, such that the apparent thickness of the CME-flare CS ranges from 10 3 to 10 5 km (see Ciaravella et al 2013;Lin et al 2015;and Lin & Ni 2018 for more details). Ciaravella & Raymond (2008) noticed that observational data in different wavelengths for the same event gave the same value of the CS thickness.…”

“…However, Raymond et al (2017) argued that the hot plasma inside the CS is prohibited from leaking outside by the electric field in the slow-mode shock should the Petschek reconnection take place through the CS, therefore the role of the thermal halo is often overestimated. Numerical calculations by Ni et al (2016) also indicated the limited impact of the thermal halo on measuring d (see also the detailed discussions of Lin & Ni 2018).…”

“…Vršnak et al (2009) studied three events occurring on 2005 June 26, 2002 January 8, and 2003 November 10, respectively, and found that the values of d¢ varied from 7 × 10 4 km to 2.1 × 10 5 . They showed that a CS forms as the associated closed coronal magnetic field is severely stretched by the eruption; the CS is thus typically highly planar, and no obvious warping occurs in the eruption, although various small-scale structures exist inside the sheet (see also the discussions of Lin & Ni 2018). The results of Vršnak et al (2009) suggest that the impact of the complex structure of the CS on measuring d may yield d¢ differing from d by only a factor of a single digit.…”

“…Numerical simulations by Seaton & Forbes (2009), Reeves et al (2010), andNi et al (2012) confirmed this result, and the CS is in fact embedded in the thermal halo. This implies that d¢ is actually the scale of the halo, not that of the CS itself (see the detailed discussions by Lin et al 2015 andLin &Ni 2018).…”

In Situ Detection of the Solar Eruption: Lay a Finger on the Sun

“…Lin [15] ß [11,25,26] . Lin [18,19] The current sheet is not only the region where the magnetic fields of opposite polarity annihilate each other, but also an essential intermedium connecting the solar flare to CME. From references [14] or [15])…”