Current Sheet Structures Observed by the TESIS EUV Telescope During A Flux Rope Eruption on the Sun

TL;DR

This study uses TESIS EUV observations to analyze current sheet structures during a solar flux rope eruption, revealing complex magnetic and thermal features that align with MHD simulations.

Contribution

It provides detailed imaging of the current sheet and flux rope structure during eruption, highlighting complex temperature distributions and dynamic features.

Findings

Flux rope had a spiral shape with variable radius.

The flux rope exhibited a complex temperature structure, contradicting previous assumptions.

A Y-structure appeared below the flux rope, matching MHD simulation predictions.

Abstract

We use the TESIS EUV telescope to study the current sheet signatures observed during flux rope eruption. The special feature of the TESIS telescope was its ability to image the solar corona up to a distance of 2 $R_\odot$ from the Sun's center in the Fe 171 \AA\ line. The Fe 171 \AA\ line emission illuminates the magnetic field lines, and the TESIS images reveal the coronal magnetic structure at high altitudes. The analyzed CME had a core with a spiral-flux rope-structure. The spiral shape indicates that the flux rope radius varied along its length. The flux rope had a complex temperature structure: cold legs (70 000 K, observed in He 304 \AA\ line) and a hotter core (0.7 MK, observed in Fe 171 \AA\ line). Such structure contradicts the common assumption that the CME core is a cold prominence. When the CME impulsively accelerated, a dark double Y-structure appeared below the flux rope. The Y-structure timing, location, and morphology agree with the previously performed MHD simulations of the current sheet. We interpreted the Y-structure as a hot envelope of the current sheet and hot reconnection outflows. The Y-structure had a thickness 6.0 Mm. Its length increased over time from 79 Mm to more than 411 Mm.