Hinode/Extreme-Ultraviolet Imaging Spectrometer Observations of the Temperature Structure of the Quiet Corona

Abstract

We present a Differential Emission Measure (DEM) analysis of the quiet solar corona on disk using data obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on {\it Hinode}. We show that the expected quiet Sun DEM distribution can be recovered from judiciously selected lines, and that their average intensities can be reproduced to within 30%. We present a subset of these selected lines spanning the temperature range $\log$ T = 5.6 to 6.4 K that can be used to derive the DEM distribution reliably. The subset can be used without the need for extensive measurements and the observed intensities can be reproduced to within the estimated uncertainty in the pre-launch calibration of EIS. Furthermore, using this subset, we also demonstrate that the quiet coronal DEM distribution can be recovered on size scales down to the spatial resolution of the instrument (1$"$ pixels). The subset will therefore be useful for studies of small-scale spatial inhomogeneities in the coronal temperature structure, for example, in addition to studies requiring multiple DEM derivations in space or time. We apply the subset to 45 quiet Sun datasets taken in the period 2007 January to April, and show that although the absolute magnitude of the coronal DEM may scale with the amount of released energy, the shape of the distribution is very similar up to at least $\log$ T $\sim$ 6.2 K in all cases. This result is consistent with the view that the {\it shape} of the quiet Sun DEM is mainly a function of the radiating and conducting properties of the plasma and is fairly insensitive to the location and rate of energy deposition. This {\it universal} DEM may be sensitive to other factors such as loop geometry, flows, and the heating mechanism, but if so they cannot vary significantly from quiet Sun region to region.

Version accepted by ApJ and published in ApJ 705. Abridged abstract

References in corpus (12)

• Ionization balance for optically thin plasmas: rate coefficients for all atoms and ions of the elements H to Ni
• Ionisation state, excited populations and emission of impurities in dynamic finite density plasmas. I: The generalised collisional-radiative model for light elements
• A new approach to analyzing solar coronal spectra and updated collisional ionization equilibrium calculations. II. Additional ionization rate coefficients
• EUV emission lines and diagnostics observed with Hinode/EIS
• High precision density measurements in the solar corona: I. Analysis methods and results for Fe XII and Fe XIII
• Temperature and Emission-Measure Profiles Along Long-Lived Solar Coronal Loops Observed with TRACE
• Observations of Active Region Loops with the EUV Imaging Spectrometer on Hinode
• Transition region features observed with Hinode/EIS
• The Temperature and Density Structure of the Solar Corona. I. Observations of the Quiet Sun with the EUV Imaging Spectrometer (EIS) on Hinode
• New EUV Fe IX emission line identifications from Hinode/EIS
• The element abundance FIP effect in the quiet Sun
• ADAS analysis of the differential emission measure structure of the inner solar corona. II. A study of the `quiet Sun' inhomogeneities from SOHO CDS-NIS spectra

Cited by in corpus (38)

• Solar UV and X-Ray Spectral Diagnostics
• Full-Sun observations for identifying the source of the slow solar wind
• Observing coronal nanoflares in active region moss
• Constraints on the Heating of High Temperature Active Region Loops: Observations from Hinode and SDO
• The Multi-slit Approach to Coronal Spectroscopy with the Multi-slit Solar Explorer (MUSE)
• Plasma composition in a sigmoidal anemone active region
• Coronal Temperature Diagnostic Capability of the Hinode/X-Ray Telescope Based on Self-Consistent Calibration
• Velocity measurements for a solar active region fan loop from Hinode/EIS observations
• Temperature distribution of a non-flaring active region from simultaneous Hinode XRT and EIS observations
• Hinode/EIS spectroscopic validation of very hot plasma imaged with Solar Dynamics Observatory in non-flaring active region cores
• FIP Bias Evolution in a Decaying Active Region
• Impact of Type II Spicules in the Corona: Simulations and Synthetic Observables
• IRIS observations of short-term variability in moss associated with transient hot coronal loops
• Investigating the reliability of coronal emission measure distribution diagnostics using 3D radiative MHD simulations
• EUV spectral line formation and the temperature structure of active region fan loops: observations with Hinode/EIS and SDO/AIA
• The coronal source of extreme-ultraviolet line profile asymmetries in solar active region outflows
• High spatial resolution FeXII observations of solar active region
• Extreme-ultraviolet bursts and nanoflares in the quiet-Sun transition region and corona
• Are Chromospheric Nanoflares a Primary Source of Coronal Plasma?
• Coronal Elemental Abundances in Solar Emerging Flux Regions
• Transition Region Abundance Measurements During Impulsive Heating Events
• Signatures of the slow solar wind streams from active regions in the inner corona
• The drivers of active region outflows into the slow solar wind
• Active Region Moss: Doppler Shifts from Hinode/EIS Observations
• Chromospheric evaporation and phase mixing of Alfvén waves in coronal loops
• Monte Carlo Markov Chain DEM reconstruction of isothermal plasmas
• Observations of the Quiet Sun During the Deepest Solar Minimum of the Past Century with Chandrayaan-2 XSM -- Elemental Abundances in the Quiescent Corona
• Magnetic loops above a small flux-emerging region observed by IRIS, Hinode and SDO
• EUV Emission and Scattered Light Diagnostics of Equatorial Coronal Holes as Seen by Hinode/EIS
• Role of small-scale impulsive events in heating the X-ray bright points of the quiet Sun
• Electron Densities in the Solar Corona Measured Simultaneously in the Extreme-Ultraviolet and Infra-Red
• Coronal Abundances in an Active Region: Evolution and Underlying Chromospheric and Transition Region Properties
• Properties of the diffuse emission around warm loops in solar active regions
• High Resolution Observations of the Low Atmospheric Response to Small Coronal Heating Events in an Active Region Core
• Properties of EUV Imaging Spectrometer (EIS) Slot Observations
• Solar cycle observations of the Neon abundance in the Sun-as-a-star
• The Quiet-Sun DEM Under Kappa: Diagnostic Degeneracy and the Failure of the Conductive Closure
• Investigating the Relationship Between Physical Properties and Spatial Irregularities at Coronal Hole Boundaries