  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.
