4 research outputs found
Predictions of DKIST/DL-NIRSP observations for an off-limb kink-unstable coronal loop
This is the author accepted manuscript. The final version is available from the American Astronomical Society via the DOI in this record.Synthetic intensity maps are generated from a 3D kink-unstable
ux rope simulation using several
DKIST/DL-NIRSP spectral lines to make a prediction of the observational signatures of energy transport
and release. The reconstructed large eld-of-view intensity mosaics and single tile sit-and-stare
high-cadence image sequences show detailed, ne-scale structure and exhibit signatures of wave propagation,
redistribution of heat,
ows and ne-scale bursts. These ne-scale bursts are present in the
synthetic Doppler velocity maps and can be interpreted as evidence for small-scale magnetic reconnection
at the loop boundary. The spectral lines reveal the di erent thermodynamic structures of the loop,
with the hotter lines showing the loop interior and braiding, and the cooler lines showing the radial
edges of the loop. The synthetic observations of DL-NIRSP are found to preserve the radial expansion
and hence the loop radius can be measured accurately. The electron number density can be estimated
using the intensity ratio of the Fe xiii lines at 10747 and 10798 A. The estimated density from this
ratio is correct to within 10% during the later phases of the evolution, however it is less accurate
initially when line-of-sight density inhomogeneities contribute to the Fe xiii intensity, resulting in an
overprediction of the density by 30%. The identi ed signatures are all above a conservative estimate
for instrument noise and therefore will be detectable. In summary, we have used forward modelling
to demonstrate that the coronal o -limb mode of DKIST/DL-NIRSP will be able to detect multiple
independent signatures of a kink-unstable loop and observe small-scale transient features including
loop braiding/twisting and small-scale reconnection events occurring at the radial edge of the loop.BS was supported
by the STFC grant ST/M000826/1. PRY acknowledges
funding from NASA grant NNX15AF25G.
GJJB, ES and JAM acknowledge STFC for IDL support
as well as support via ST/L006243/1