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Title: An estimate of the coronal magnetic field near a solar coronal mass ejection from low-frequency radio observations

We report ground-based, low-frequency (<100 MHz) radio imaging, spectral, and polarimeter observations of the type II radio burst associated with the solar coronal mass ejection (CME) that occurred on 2013 May 2. The spectral observations indicate that the burst has fundamental (F) and harmonic (H) emission components with split-band and herringbone structures. The imaging observations at 80 MHz indicate that the H component of the burst was located close to leading edge of the CME at a radial distance of r ≈ 2 R {sub ☉} in the solar atmosphere. The polarimeter observations of the type II burst, also at 80 MHz, indicate that the peak degree of circular polarization (dcp) corresponding to the emission generated in the corona ahead of and behind the associated MHD shock front are ≈0.05 ± 0.02 and ≈0.1 ± 0.01, respectively. We calculated the magnetic field B in the above two coronal regions by adopting the empirical relationship between the dcp and B for the harmonic plasma emission and the values are ≈(0.7-1.4) ± 0.2 G and ≈(1.4-2.8) ± 0.1 G, respectively.
Authors:
; ; ;  [1] ;  [2]
  1. Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034 (India)
  2. Solar Physics Laboratory, NASA/GSFC, Code 671, Greenbelt, MD (United States)
Publication Date:
OSTI Identifier:
22370324
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPUTERIZED SIMULATION; DISTANCE; EMISSION; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; MASS; MASS TRANSFER; PLASMA; POLARIMETERS; POLARIZATION; RADIO TELESCOPES; SOLAR ATMOSPHERE; SOLAR CORONA; SUN