Modeling the quiet Sun cell and network emission with ALMA

Abstract

ALMA observations of the Sun at mm-$\lambda$ offer a unique opportunity to investigate the temperature structure of the solar chromosphere. In this article we expand our previous work on modeling the chromospheric temperature of the quiet Sun, by including measurements of the brightness temperature in the network and cell interiors, from high resolution ALMA images at 3 mm (Band 3) and 1.26 mm (Band 6). We also examine the absolute calibration of ALMA full-disk images. We suggest that the brightness temperature at the center of the solar disk in Band 6 is $\sim 440$ K above the value recommended by White et al. (2017) and we give improved results for the electron temperature variation of the average quiet Sun with optical depth, as well as the derived spectrum at the center of the disk. We found that the electron temperature in the network is considerably lower than predicted by model F of Fontenla et al. (1993) and that of the cell interior considerably higher than predicted by model A. Depending upon the network/cell segregation scheme, the electron temperature difference between network and cell at $\tau =1$ (100 GHz) is from $\sim$660 to $\sim$1550 K, compared to $\sim$3280 K predicted by the models; similarly, the $T_e$ ratio is from $\sim$1.10, to 1.24, against $\sim$1.55 of the model prediction. We also found that the network/cell $T_e(\tau )$ curves diverge as $\tau$ decreases, indicating an increase of contrast with height and possibly a steeper temperature rise in the network than in the cell interior.

arXiv commentAccepted, Astronomy & Astrophysics

References in corpus (15)

• The stellar atmosphere simulation code Bifrost
• STiC -- A multi-atom non-LTE PRD inversion code for full-Stokes solar observations
• Observing the Sun with the Atacama Large Millimeter-submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping
• Center-to-limb observations of the Sun with ALMA
• Inter-network regions of the Sun at millimetre wavelengths
• The Sun at millimeter wavelengths I. Introduction to ALMA Band 3 observations
• Observations of solar chromospheric oscillations at 3 mm with ALMA
• ALMA detection of dark chromospheric holes in the quiet Sun
• First high-resolution look at the quiet Sun with ALMA at 3 mm
• Transient brightenings in the quiet Sun detected by ALMA at 3 mm
• The Brightness Temperature of the Quiet Solar Chromosphere at 2.6 mm
• First solar observations with ALMA
• Solar Radius at Subterahertz Frequencies and its Relation to Solar Activity
• Measurement of the Height of the Chromospheric Network Emission from Solar Dynamics Observatory Images
• Structure of the transition region and the low corona from TRACE and SDO observations near the limb

Cited by in corpus (11)

• An overall view of temperature oscillations in the solar chromosphere with ALMA
• ALMA observations of the variability of the quiet Sun at millimeter wavelengths
• A first look at the submillimeter Sun with ALMA
• Simultaneous ALMA-Hinode-IRIS observations on footpoint signatures of a soft X-ray loop-like microflare
• Subterahertz Radius and Limb Brightening of the Sun Derived from SST and ALMA
• Propagation of transverse waves in the solar chromosphere probed at different heights with ALMA sub-bands
• Flares detected in ALMA single-dish images of the Sun
• Where is the base of the Transition Region? Evidence from TRACE, SDO, IRIS and ALMA observations
• ALMA Observations of Solar Spicules in a Polar Coronal Hole
• Utilizing the slope of the brightness temperature continuum as a diagnostic tool of solar ALMA observations
• The Solar ALMA Science Archive (SALSA)