We report observations of circularly polarized emission from the solar corona at 77?MHz during the periods 2006 August 11-18, 2006 August 23-29, and 2007 May 16-22 in the minimum phase between the sunspot cycles 23 and 24. The observations were carried out with the east-west one-dimensional radio polarimeter at the Gauribidanur observatory located about 100?km north of Bangalore. Two-dimensional imaging observations at 77?MHz during the same period with the radioheliograph at the same observatory revealed that the emission region co-rotated with the Sun during the three aforementioned periods. Their rotation rates, close to the central meridian on the Sun, are 46, 52, and 49 ± 05 per day, respectively. We derived the radial distance of the region from the above observed rotation rates and the corresponding values are ≈1.24 ± 0.03 R ☉ (2006 August 11-18), ≈1.40 ± 0.03 R ☉ (2006 August 23-29), and ≈1.32 ± 0.03 R ☉ (2007 May 16-22). The estimated lower limit for the magnetic field strength at the above radial distances and periods are ≈1.1, 0.6, and 0.9 G, respectively.
展开▼
