Spectroscopic Observations of a Coronal Loop: Basic Physical Plasma Parameters Along the Full Loop Length

TL;DR

This study uses spectroscopic data from Hinode/EIS to measure key plasma parameters along a full coronal loop, providing new constraints on models of solar plasma heating and mass transfer.

Contribution

It offers detailed measurements of electron density, temperature, and other parameters along the entire length of a coronal loop, enhancing understanding of loop structure and plasma dynamics.

Findings

Determined plasma parameters along the full loop length.

Identified whether the loop is over-dense or under-dense.

Provided constraints for coronal loop modeling.

Abstract

Coronal loops are the basic structures of the solar transition region and corona. The understanding of physical mechanism behind the loop heating, plasma flows, and filling are still considered a major challenge in the solar physics. The mechanism(s) should be able to supply mass to the corona from the chromosphere and able to heat the plasma over 1 MK within the small distance of few hundred km from the chromosphere to the corona. This problem makes coronal loops an interesting target for detailed study. In this study, we focus on spectroscopic observations of a coronal loop, observed in its full length, in various spectral lines as recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on-board Hinode. We derive physical plasma parameters such as electron density, temperature, pressure, column depth, and filling factors along the loop length from one foot-point to the another. The obtained parameters are used to infer whether the observed coronal loop is over-dense or under-dense with respect to gravitational stratification of the solar atmosphere. These new measurements of physical plasma parameters, from one foot-point to another, provide important constraints on the modeling of the mass and energy balance in the coronal loops.