A cold, tenuous solar flare: Acceleration without heating

Gregory Fleishman; Eduard P. Kontar; Gelu Nita; Dale Gary

doi:10.1088/2041-8205/731/1/L19

A cold, tenuous solar flare: Acceleration without heating

Gregory Fleishman, Eduard P. Kontar, Gelu Nita, Dale Gary

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Abstract

We report the observation of an unusual cold, tenuous solar flare, which reveals itself via numerous and prominent non-thermal manifestations, while lacking any noticeable thermal emission signature. RHESSI hard X-rays and 0.1-18 GHz radio data from OVSA and Phoenix-2 show copious electron acceleration (10³⁵ electrons s^-1 above 10 keV) typical for GOES M-class flares with electrons energies up to 100 keV, but GOES temperatures not exceeding 6.1 MK. The imaging, temporal, and spectral characteristics of the flare have led us to a firm conclusion that the bulk of the microwave continuum emission from this flare was produced directly in the acceleration region. The implications of this finding for the flaring energy release and particle acceleration are discussed.

Original language	English (US)
Article number	L19
Journal	Astrophysical Journal Letters
Volume	731
Issue number	1 PART II
DOIs	https://doi.org/10.1088/2041-8205/731/1/L19
State	Published - Apr 10 2011

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

Sun: flares
Sun: radio radiation
acceleration of particles
diffusion
magnetic fields
turbulence

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10.1088/2041-8205/731/1/L19

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abstract = "We report the observation of an unusual cold, tenuous solar flare, which reveals itself via numerous and prominent non-thermal manifestations, while lacking any noticeable thermal emission signature. RHESSI hard X-rays and 0.1-18 GHz radio data from OVSA and Phoenix-2 show copious electron acceleration (1035 electrons s-1 above 10 keV) typical for GOES M-class flares with electrons energies up to 100 keV, but GOES temperatures not exceeding 6.1 MK. The imaging, temporal, and spectral characteristics of the flare have led us to a firm conclusion that the bulk of the microwave continuum emission from this flare was produced directly in the acceleration region. The implications of this finding for the flaring energy release and particle acceleration are discussed.",

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T2 - Acceleration without heating

AU - Fleishman, Gregory

AU - Kontar, Eduard P.

AU - Nita, Gelu

AU - Gary, Dale

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Y1 - 2011/4/10

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AB - We report the observation of an unusual cold, tenuous solar flare, which reveals itself via numerous and prominent non-thermal manifestations, while lacking any noticeable thermal emission signature. RHESSI hard X-rays and 0.1-18 GHz radio data from OVSA and Phoenix-2 show copious electron acceleration (1035 electrons s-1 above 10 keV) typical for GOES M-class flares with electrons energies up to 100 keV, but GOES temperatures not exceeding 6.1 MK. The imaging, temporal, and spectral characteristics of the flare have led us to a firm conclusion that the bulk of the microwave continuum emission from this flare was produced directly in the acceleration region. The implications of this finding for the flaring energy release and particle acceleration are discussed.

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KW - magnetic fields

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A cold, tenuous solar flare: Acceleration without heating

Abstract

All Science Journal Classification (ASJC) codes

Keywords

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