High-resolution Observations of a Flux Rope with the Interface Region Imaging Spectrograph

Abstract

We report the observations of a flux rope at transition region temperatures with the \emph{Interface Region Imaging Spectrograph} (IRIS) on 30 August 2014. Initially, magnetic flux cancellation constantly took place and a filament was activated. Then the bright material from the filament moved southward and tracked out several fine structures. These fine structures were twisted and tangled with each other, and appeared as a small flux rope at 1330 Å, with a total twist of about 4$\pi$. Afterwards, the flux rope underwent a counter-clockwise (viewed top-down) unwinding motion around its axis. Spectral observations of C {\sc ii} 1335.71 Å at the southern leg of the flux rope showed that Doppler redshifts of 6$-$24 km s${}^{-1}$ appeared at the western side of the axis, which is consistent with the counter-clockwise rotation motion. We suggest that the magnetic flux cancellation initiates reconnection and some activation of the flux rope. The stored twist and magnetic helicity of the flux rope are transported into the upper atmosphere by the unwinding motion in the late stage. The small-scale flux rope (width of 8.3${}^{\prime \prime }$) had a cylindrical shape with helical field lines, similar to the morphology of the large-scale CME core (width of 1.54 $R_{\odot }$) on 2 June 1998. This similarity shows the presence of flux ropes of different scales on the Sun.

15 pages, 7 figures, Solar Physics, in press

References in corpus (12)

• The Interface Region Imaging Spectrograph (IRIS)
• Emergence of a Helical Flux Rope Under an Active Region Prominence
• High-resolution Observations of the Shock Wave Behavior for Sunspot Oscillations with the Interface Region Imaging Spectrograph
• Formation of a Double-decker Magnetic Flux Rope in the Sigmoidal Solar Active Region 11520
• Multiwavelength observations of a partially eruptive filament on 2011 September 8
• Direct Observations of Tether-cutting Reconnection During a Major Solar Event From 2014 February 24 to 25
• Formation of Compound Flux Rope by The Merging of Two Filament Channels, Associated Dynamics and its Stability
• Conversion from mutual helicity to self-helicity observed with IRIS
• Direct Evidence of an Eruptive, Filament-Hosting Magnetic Flux Rope Leading to a Fast Solar Coronal Mass Ejection
• Kink instability evidenced by analyzing the leg rotation of a filament
• First High-resolution Spectroscopic Observations of an Erupting Prominence Within a Coronal Mass Ejection by the Interface Region Imaging Spectrograph (IRIS)
• Multiwavelength observation of a large-scale flux rope eruption above kinked mini-filament

Cited by in corpus (10)

• Origin and Structures of Solar Eruptions I: Magnetic Flux Rope (Invited Review)
• Helical Kink Instability in a Confined Solar Eruption
• The formation of an inverse S-shaped active-region filament driven by sunspot motion and magnetic reconnection
• Non-equilibrium Flux Rope Formation by Confined Flares Preceding a Solar Coronal Mass Ejection
• Light Walls Around Sunspots Observed by the Interface Region Imaging Spectrograph
• Multi-wavelength Observation of a Failed Eruption from a Helical Kink-unstable Prominence
• Solar Total Eclipse of 21 August 2017: Study of the Inner Corona Dynamical Events Leading to a CME
• Helical Kink Instability in the confined Solar Eruption on 2002 May 27
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)
• Multi-wavelength and Dual-perspective Observations of Eruption and Untwisting of Two Homologous Magnetic Flux Ropes