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We present here one of the first high resolution spectroscopic observationsof coronal rain, performed with the CRISP instrument at the Swedish SolarTelescope. This work constitutes the first attempt to assess the importance ofcoronal rain in the understanding of the coronal magnetic field in activeregions. A large statistical set is obtained in which dynamics (totalvelocities and accelerations), shapes (lengths and widths), trajectories(angles of fall) and thermodynamic properties (temperatures) of thecondensations are derived. Specifically, we find that coronal rain is composedof small and dense chromospheric cores with average widths and lengths of 310km and 710 km respectively, average temperatures below 7000 K, displaying abroad distribution of falling speeds with an average of 70 km/s andaccelerations largely below the effective gravity along loops. Throughestimates of the ion-neutral coupling in the blobs we show that coronal rainacts as a tracer of the coronal magnetic field, thus supporting themulti-strand loop scenario, and acts as a probe of the local thermodynamicconditions in loops. We further find that the cooling in neighboring strandsoccurs simultaneously in general suggesting a similar thermodynamic evolutionamong strands, which can be explained by a common footpoint heating process.Constraints for coronal heating models of loops are thus provided. Estimates ofthe fraction of coronal volume with coronal rain give values between 7% and30%. Estimates of the occurrence time of the phenomenon in loops set timesbetween 5 and 20 hours, implying that coronal rain may be a common phenomenon,in agreement with the frequent observations of cool downflows in EUV lines. Thecoronal mass drain rate in the form of coronal rain is estimated to be on theorder of 5x10^9 g/s, a significant quantity compared to the estimate of massflux into the corona from spicules.

astrophysical journal/the astrophysical journal

Observing the fine structure of loops through high resolution  spectroscopic observations of coronal rain with the CRISP instrument at the  Swedish Solar Telescope