FLARE RIBBON ENERGETICS IN THE EARLY PHASE OF AN SDO FLARE

• Published in: The Astrophysical journal Vol. 771; no. 2; pp. 1 - 13
• Main Authors: Fletcher, L, Hannah, I G, Hudson, H S, Innes, D E
• Format: Journal Article
• Language: English
• Published: United States 10-07-2013
• Subjects: Approximation; APPROXIMATIONS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BREMSSTRAHLUNG; CHROMOSPHERE; DENSITY; EMISSION; ENERGY ABSORPTION; ENERGY ACCOUNTING; ENERGY LOSSES; EXCITATION; EXTREME ULTRAVIOLET RADIATION; Flares; GAMMA RADIATION; GRAY ENERGY; HARD X RADIATION; KEV RANGE; Mathematical analysis; PLASMA; PRECIPITATION; Ribbons; SOLAR FLARES; SUN; TURBULENCE; WAVELENGTHS; X-rays
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/771/2/104

We aim to determine the properties of the heated plasma in the flare ribbons, and to understand the partition of the power input into radiative and conductive losses. Using GOES, SDO/EVE, SDO/AIA, and RHESSI, we measure the temperature, emission measure (EM), and differential emission measure of the flare ribbons, and deduce approximate density values. We deduce the existence of a substantial amount of plasma at 10 MK in the flare ribbons, during the pre-impulsive and early-impulsive phase of the flare. The average column EM of this hot component is a few times 10 super(28) cm super(-5), and we can calculate that its predicted conductive losses dominate its measured radiative losses. Independent of the standard collisional thick-target electron beam interpretation, the observed non-thermal X-rays can be provided if one electron in 10 super(3)-10 super(4) in the 10 MK (1 keV) ribbon plasma has an energy above 10 keV.