Observational evidence for hotter transition region loops within the supergranular network

Abstract

view Abstract Citations (30) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observational Evidence for Hotter Transition Region Loops within the Supergranular Network Dowdy, James F., Jr. Abstract We correlate EUV spectroheliograms of the quiet sun taken by the Harvard EUV Spectroheliometer on Skylab with a magnetogram taken within 15-20 minutes by the 40 channel magnetograph at Kitt Peak. Focus is on the O VI and Ne VII ions which are formed in the hotter transition region and the Mg x ion which is formed in the corona. Since no imaged observations in lines from T = 2 x 10 exp 5 - 10 exp 6 K temperature region have been made since Skylab, these data are unique in providing opportunities to investigate the hotter transition region and its relationship to the corona. The signature of an EUV intranetwork loop is a small EUV brightening located on the neutral line of a small magnetic bipole within the supergranular network. The data clearly show such features. Some of these features are visible at coronal temperatures, indicating that network loops can reach 10 exp 6 K. Others are bright in the lines formed below 10 exp 6 K but occur in regions of depleted coronal emission, which cannot be explained by models based on back-heating from a large-scale corona. We conclude that some fraction of the quiet solar EUV output is generated within network loops that are effectively insulated from the corona. Publication: The Astrophysical Journal Pub Date: July 1993 DOI: 10.1086/172842 Bibcode: 1993ApJ...411..406D Keywords: Coronal Loops; Extreme Ultraviolet Radiation; Solar Granulation; Solar Magnetic Field; Spectroheliographs; Ultraviolet Spectra; Energy Transfer; High Temperature Plasmas; Solar Corona; Solar Temperature; Solar Physics; SUN: MAGNETIC FIELDS; SUN: TRANSITION REGION; SUN: UV RADIATION full text sources ADS |