Jeffrey W. Brosius and Stephen M. White 2006 ApJ 641 L69 doi:10.1086/503774
Jeffrey W. Brosius1 and Stephen M. White2
Show affiliationsWe measure coronal magnetic field strengths of 1750 G at a height of 8000 km above a large sunspot in NOAA AR 10652 at the west solar limb on 2004 July 29 using coordinated observations with the Very Large Array, the Transition Region and Coronal Explorer, and three instruments (CDS, EIT, MDI) aboard the Solar and Heliospheric Observatory. This observation is the first time that coronal radio brightness temperatures have been analyzed in a 15 GHz solar radio source projected above the limb. Observations at 8 GHz yield coronal magnetic field strengths of 960 G at a height of 12,000 km. The field strength measurements combine to yield a magnetic scale height LB = 6900 km. The radio brightness temperature maxima are located away from a sunspot plume that appears bright in EUV line emission formed at temperatures around several ×105 K. We use the density-sensitive emission-line intensity ratio of O IV 625.8 Å/554.5 Å to derive an electron density ne (in units of cm-3) of log ne = 10.1 ± 0.2 at the base of the plume.
Sun: activity; Sun: corona; Sun: magnetic fields; Sun: radio radiation; sunspots; Sun: UV radiation
Issue 1 (2006 April 10)
Received 2006 February 8, accepted for publication 2006 March 1
Published 2006 March 21
Jeffrey W. Brosius and Stephen M. White 2006 ApJ 641 L69
David S. Rupke et al. 2005 ApJ 632 751
K. Itoh 2003 Nucl. Fusion 43 1710
R Mélin et al 2003 J. Phys.: Condens. Matter 15 5591
E Di Fabrizio et al 2004 J. Phys.: Condens. Matter 16 S3517
Koji Asami and Akihiko Irimajiri 2000 Phys. Med. Biol. 45 3285
Dietrich Schlichthärle 2001 Meas. Sci. Technol. 12 2211
D W O Rogers 2006 Phys. Med. Biol. 51 R287
K Bera et al 2001 J. Phys. D: Appl. Phys. 34 1479
S H Liao et al 2003 Supercond. Sci. Technol. 16 1426