The role of small-scale surface motions in the transfer of twist to a solar jet from a remote stable flux rope

Abstract

Jets often have a helical structure containing ejected plasma that is both hot and also cooler and denser than the corona. Various mechanisms have been proposed to explain how jets are primarily attributed to a magnetic reconnection between the emergence of magnetic flux and environment or that of twisted photospheric motions that bring the system into a state of instability. Multi-wavelength observations of a twisted jet observed with AIA and IRIS were used to understand how the twist was injected into the jet. We followed the magnetic history of the active region based on the analysis of HMI vector magnetic field computed with the UNNOFIT code. This region is the result of the collapse of two emerging magnetic fluxes (EMFs) overlaid by arch filament systems that have been well-observed with AIA, IRIS, and NVST in H-alpha. In the magnetic field maps, we found evidence of the pattern of a long sigmoidal flux rope (FR) along the polarity inversion line between the two EMFs, which is the site of the reconnection. Before the jet, an extension of the FR was present and a part of it was detached and formed a small bipole with a bald patch (BP) region, which dynamically became an X-current sheet over the dome of one EMF where the reconnection took place. At the time of the reconnection, the Mg II spectra exhibited a strong extension of the blue wing that is decreasing over a distance of 10 Mm (from -300 km/s to a few km/s). This is the signature of the transfer of the twist to the jet. A comparison with numerical magnetohydrodynamics (MHD) simulations confirms the existence of the long FR. We conjecture that there is a transfer of twist to the jet during the extension of the FR to the reconnection site without FR eruption. There connection would start in the low atmosphere in the BP reconnection region and extend at an X-point along the current sheet formed above.

22 pages, 13 figures, Astronomy and Astrophysics

References in corpus (18)

• Solar Coronal Jets: Observations, Theory, and Modeling
• Hot Explosions in the Cool Atmosphere of the Sun
• Jets in coronal holes: Hinode observations and 3D computer modelling
• STEREO/SECCHI Stereoscopic Observations Constraining the Initiation of Polar Coronal Jets
• Blobs in recurring EUV jets
• Ellerman bombs and UV bursts: transient events in chromospheric current sheets
• A model for straight and helical solar jets: II. Parametric study of the plasma beta
• Surges and Si IV bursts in the solar atmosphere. Understanding IRIS and SST observations through RMHD experiments
• A Cancellation Nanoflare Model for Solar Chromospheric and Coronal Heating II. 2D Theory and Simulations
• A case-study of multi-temperature coronal jets for emerging flux MHD models
• Blowout Jets and Impulsive Eruptive Flare in a Bald-Patch Topology
• Observational Evidence of Magnetic Reconnection for Brightenings and Transition Region Arcades in IRIS observations
• Conversion from mutual helicity to self-helicity observed with IRIS
• IRIS Observations of Spicules and Structures Near the Solar Limb
• Imaging and spectral study on the null point of a fan-spine structure during a solar flare
• Slippage of Jets Explained by the Magnetic Topology of NOAA Active Region 12035
• Flare reconnection-driven magnetic field and Lorentz force variations at the Sun's surface
• Electric current evolution at the footpoints of solar eruptions

Cited by in corpus (10)

• The European Solar Telescope
• Solar jets observed with the Interface Region Imaging Spectrograph (IRIS)
• Spectroscopic observations of a flare-related coronal jet
• Multi thermal atmosphere of a mini solar flare during magnetic reconnection observed with IRIS
• High-resolution observations of recurrent jets from an arch filament system
• Generic low-atmosphere signatures of swirled-anemone jets
• Interaction of solar jets with filaments: Triggering of large-amplitude filament oscillations
• Spectroscopic investigations of a filament reconnecting with coronal loops during a two-ribbon solar flare
• Simulation of a Solar Jet Formed from an Untwisting Flux Rope Interacting with a Null Point
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)