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

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.

accepted for publication in ApJ

References in corpus (5)

• High precision density measurements in the solar corona: I. Analysis methods and results for Fe XII and Fe XIII
• Observations of Active Region Loops with the EUV Imaging Spectrometer on Hinode
• Are Chromospheric Nanoflares a Primary Source of Coronal Plasma?
• Emission Measure Distribution for Diffuse Regions in Solar Active Regions
• On the Area Expansion of Magnetic Flux-Tubes in Solar Active Regions

Cited by in corpus (2)

• Fan Loops Observed by IRIS, EIS and AIA
• Spectroscopic evidence of Alfvén wave damping in the off-limb solar corona