A DECADE OF SOLAR TYPE III RADIO BURSTS OBSERVED BY THE NANC, AY RADIOHELIOGRAPH 1998-2008

作者：Saint Hilaire P^*; Vilmer N; Kerdraon A

来源：Astrophysical Journal, 2013, 762(1): 60.

DOI：10.1088/0004-637X/762/1/60

• acceleration of particles
• radiation mechanisms: non-thermal
• Sun: corona
• Sun: radio radiation

We present a statistical survey of almost 10,000 radio type III bursts observed by the Nan, cay Radioheliograph from 1998 to 2008, covering nearly a full solar cycle. In particular, sources sizes, positions, and fluxes were examined. We find an east-west asymmetry in source positions that could be attributed to a 6 degrees +/- 1 degrees eastward tilt of the magnetic field, that source FWHM sizes s roughly follow a solar-cycle-averaged distribution (dN/ds) approximate to 14v(-3.3)s(-4) arcmin(-1) day(-1), and that source fluxes closely follow a solar-cycle-averaged (dN/ds(v)) approximate to 0.34(v)(-2.9)S(v)(-1.7) sfu(-1) day(-1) distribution (when. is in GHz, s in arcminutes, and S. in sfu). Fitting a barometric density profile yields a temperature of 0.6 MK, while a solar wind-like (alpha h(-2)) density profile yields a density of 1.2 x 10(6) cm(-3) at an altitude of 1 R-S, assuming harmonic emission. Finally, we found that the solar-cycle-averaged radiated type III energy could be similar in magnitude to that radiated by nanoflares via non-thermal bremsstrahlung processes, and we hint at the possibility that escaping electron beams might carry as much energy away from the corona as is introduced into it by accelerated nanoflare electrons.

• 出版日期2013-1-1