The dynamical behaviour of a jet in an on-disk coronal hole observed with AIA/SDO

Chandrashekhar, K., Morton, Richard, Banerjee, Dipankar and Gupta, Girjesh (2014) The dynamical behaviour of a jet in an on-disk coronal hole observed with AIA/SDO. Astronomy & Astrophysics, 562. A98. ISSN 0004-6361

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Abstract

Aims. Extreme ultraviolet (EUV) jets situated in coronal holes are thought to play an important role in supplying heated material to the corona and solar wind. The multi-wavelength capabilities and high signal-to-noise ratio of detectors on board the Solar Dynamic Observatory (SDO) allow for detailed study of these jets’ evolution. We aim to exploit SDO’s capabilities to reveal information on the jet dynamics and to obtain estimates for plasma properties associated with the jets.
Methods. We studied the dynamics of an EUV jet with SDO at a coronal hole boundary. The details of the jet evolution are discussed and measurements of the jet’s parameters, e.g. length, width, life time, and outward speed, are obtained. Furthermore, automated emission measure analysis is exploited to determine estimates for the temperature and density of the jet. A propagating transverse wave supported by the jet spire is also observed. Measurements of the wave properties are exploited for magneto-seismology and are used in conjunction with the emission measure results to estimate the magnetic field strength of the jet.
Results. We present a detailed description of the jet’s evolution, with new evidence of plasma flows, prior to the jet’s initiation, along the loops at the base of the jet and also find further evidence that flows along the jet spire consist of multiple, quasi-periodic small-scale plasma ejection events. In addition, spectroscopic analysis reveal that the jet has temperatures of log 5.89 ± 0.08 K and electron densities of log 8.75 ± 0.05 cm-3. Measured properties of the transverse wave provide evidence that a strong damping of the wave occurs as it propagates along the jet spire with speeds of ~110 km s-1. The magneto-seismological inversion of the wave parameters provides values of B = 1.21 ± 0.2 G along the jet spire, which is in line with previous estimates for open fields in coronal holes.

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