Diagnostic of Homologous Solar Surge Plasma as observed by IRIS and SDO

Abstract

Surges have regularly been observed mostly in H${}_{\alpha }$ 6563~Å and Ca~{\sc ii} 8542~Å. However, surge${}^{\prime }$s response to other prominent lines of the interface-region (Mg~{\sc ii} k 2796.35~Å $\&$ h 2803.52~Å, O~{\sc iv} 1401.15~Å, Si~{\sc iv} 1402.77~Å) is not well studied. Here, the evolution and kinematics of six homologous surges are analysed using IRIS and AIA observations. These surges were observed on 7${}^{th}$ July 2014, located very close to the limb. DEM analysis is performed on these surges where the co-existence of cool (log T/K = 6.35) and relatively hot (log T/K = 6.95) components have been found at the base. This demonstrates that the bases of surges undergo substantial heating. During the emission of these surges in the above mentioned interface-region lines, being reported here for the first time, two peaks have been observed in the initial phase of emission, where one peak is found to be constant while other one as varying, i.e., non-constant (observed red to blueshifts across the surge evolution) in nature. This suggests the rotational motion of surge plasma. The heated base and rotating plasma suggests the occurrence of magnetic reconnection, most likely, as the trigger for homologous surges. During the emission of these surges, it is found that despite being optically thick (i.e., R${}_{kh}$ < 2.0), central reversal was not observed for Mg~{\sc ii} k $\&$ h lines. Further, R${}_{kh}$ increases with surge emission in time and it is found to have positive correlation with Doppler Velocity while negative with Gaussian width.

17 pages, 12 figures (9 main+3 appendix), Accepted for Publication in MNRAS

References in corpus (15)

• Chromospheric Anemone Jets as Evidence of Ubiquitous Reconnection
• Solar Coronal Jets: Observations, Theory, and Modeling
• Hot Explosions in the Cool Atmosphere of the Sun
• Thermal Diagnostics with the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory: A Validated Method for Differential Emission Measure Inversions
• On the prevalence of small-scale twist in the solar chromosphere and transition region
• RH 1.5D: a massively parallel code for multi-level radiative transfer with partial frequency redistribution and Zeeman polarisation
• Homologous Helical Jets: Observations by IRIS, SDO and Hinode and Magnetic Modeling with Data-Driven Simulations
• A model for straight and helical solar jets: II. Parametric study of the plasma beta
• Rotating Solar Jets in Simulations of Flux Emergence with Thermal Conduction
• Surges and Si IV bursts in the solar atmosphere. Understanding IRIS and SST observations through RMHD experiments
• Explosive events in active region observed by IRIS and SST/CRISP
• Explosive events associated with a surge
• Witnessing a Large-scale Slipping Magnetic Reconnection along a Dimming Channel during a Solar Flare
• IRIS Mg II Observations and Non-LTE Modeling of Off-limb Spicules in a Solar Polar Coronal Hole
• The impact of a filament eruption on nearby high-lying cool loops