Three-dimensional structures of two solar active regions from VLA observations at 2, 6, and 20 centimeter wavelengths

Abstract

view Abstract Citations (36) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Three-dimensional structures of two solar active regions from VLA observations at 2, 6, and 20 centimeter wavelengths Shevgaonkar, R. K. ; Kundu, M. R. Abstract Three-dimensional structures of two active region groups are determined from observations with the Very Large Array (VLA) at 2, 6, and 20 cm. One of the groups exhibits a single magnetic loop of length approximately 10 to the 10th cm. The 2 cm radiation is mostly thermal bremsstrahlung and originates from the footprints of the loop. The 6 and 20 cm radiation is dominated by low-harmonic gyroresonance radiation and originates from the upper portion of the legs or the top of the loop. The loop broadens toward the apex. The top of the loop is not found to be the hottest point, but two temperature maxima on either side of the loop apex are observed, which is consistent with the model proposed for long loops. From 2 and 6 cm observations it can be concluded that the electron density and temperature cannot be uniform in a plane perpendicular to the axis of the loop; the density should decrease away from the axis of the loop. Publication: The Astrophysical Journal Pub Date: August 1984 DOI: 10.1086/162320 Bibcode: 1984ApJ...283..413S Keywords: Centimeter Waves; Coronal Loops; Solar Activity; Solar Magnetic Field; Solar Radio Emission; Very Long Base Interferometry; Astronomical Maps; Bremsstrahlung; Circular Polarization; Gyrofrequency; Solar Temperature; Very Large Array (Vla); Solar Physics full text sources ADS |