Abstract:
We analyse multiwavelength and multiviewpoint observations of a helically twisted plasma
jet formed during a confined filament eruption on 2013 April 10–11. Given a rather largescale
event with its high spatial and temporal resolution observations, it allows us to clearly
understand some new physical details about the formation and triggering mechanism of
twisting jet. We identify a pre-existing flux rope associated with a sinistral filament, which
was observed several days before the event. The confined eruption of the filament within a
null-point topology, also known as an Eiffel tower (or inverted-Y) magnetic field configuration
results in the formation of a twisted jet after the magnetic reconnection near a null point. The
sign of helicity in the jet is found to be the same as that of the sign of helicity in the filament.
Untwisting motion of the reconnected magnetic field lines gives rise to the accelerating plasma
along the jet axis. The event clearly shows the twist injection from the pre-eruptive magnetic
field to the jet.
