  To study the dynamical evolution of trans-equatorial loops (TELs) using
imaging and spectroscopy. We have used the images recorded by the Atmospheric
Imaging Assembly and the Helioseismic Magnetic Imager on-board the Solar
Dynamics Observatory and spectroscopic observations taken from the
Extreme-Ultraviolet Imaging Spectrometer on-board Hinode. The data from AIA 193
{\AA} channel show that TELs are formed between AR 12230 and a newly emerging
AR 12234 and evolved during December 10-14, 2014. The xt-plots for December 12,
2014 obtained using AIA 193 {\AA} data reveal signatures of inflow and outflow
towards an X-region. High cadence AIA images also show recurrent intensity
enhancements in close proximity to the X-region (P2), which is observed to have
higher intensities for spectral lines formed at log T[K] =6.20 and voids at
other higher temperatures. The electron densities and temperatures in the
X-region (and P2) are maintained steadily at log N_e =8.5-8.7 /cc and log T[K]
=6.20, respectively. Doppler velocities in the X-region show predominant
redshifts by about 5-8 km/s when closer to the disk centre but blueshifts
(along with some zero-velocity pixels) when away from the centre. The
Full-Width-Half-Maxima (FWHM) maps reveal non-thermal velocities of about 27-30
km/s for Fe XII, Fe XIII and Fe XV lines. However, the brightest pixels have
non-thermal velocities of about 62 km/s for Fe XII and Fe XIII lines. On the
contrary, the dark X-region for Fe XV line have the highest non-thermal
velocity (roughly 115 km/s). We conclude that the TELs are formed due to
magnetic reconnection. We further note that the TELs themselves undergo
magnetic reconnection leading to reformation of loops of individual ARs.
Moreover, this study, for the first time, provides measurements of plasma
parameters in X-regions thereby providing essential constraints for theoretical
studies.
